CWSs < 100 $ 1,165,828 $ 1,165,752 $ 1,000,737 $ 1,329,787 $ 172,818 $ 172,767 $ 162,855 $ 182,839 101 500 $ 3,587,143 $ 3,587,063 $ 3,107,571 $ 4,068,277 $ 481,038 $ 480,845 $ 452,914 $ 509,265 501 1,000 $ 5,490,082 $ 5,491,175 $ 4,852,389 $ 6,139,651 $ 585,085 $ 584,957 $ 551,921 $ 618,039 1,001 3,300 $ 23,755,695 $ 23,758,484 $ 20,943,016 $ 26,639,033 $ 2,051,245 $ 2,050,955 $ 1,934,474 $ 2,168,328 3,301 10K $ 76,403,354 $ 76,408,063 $ 66,738,018 $ 86,212,410 $ 4,286,058 $ 4,286,785 $ 4,025,875 $ 4,547,476 Small $ 110,402,101 $ 110,397,632 $ 96,717,196 $ 124,270,095 $ 7,576,244 $ 7,576,111 $ 7,134,110 $ 8,015,137 10,001 50K $ 359,971,817 $ 360,167,017 $ 310,283,911 $ 409,099,856 $ 11,927,418 $ 11,928,400 $ 11,282,107 $ 12,575,388 50,001 100K $ 201,179,616 $ 201,282,461 $ 172,905,146 $ 229,091,063 $ 5,957,579 $ 5,957,462 $ 5,633,665 $ 6,279,466 100,001 1M $ 618,123,424 $ 618,346,504 $ 530,387,363 $ 704,882,504 $ 16,548,010 $ 16,554,351 $ 15,612,525 $ 17,466,980 > 1 Million $ 428,436,029 $ 428,643,237 $ 361,486,896 $ 494,697,645 $ 11,640,052 $ 11,644,134 $ 10,896,917 $ 12,371,585 Large $ 1,607,710,886 $ 1,608,184,156 $ 1,375,058,137 $ 1,837,801,080 $ 46,073,059 $ 46,088,445 $ 43,466,256 $ 48,644,297 CWS Total $ 1,718,112,988 $ 1,718,432,428 $ 1,475,240,607 $ 1,958,528,905 $ 53,649,302 $ 53,659,509 $ 50,805,019 $ 56,480,566 NTNCWSs < 100 $ 698,074 $ 697,594 $ 599,491 $ 797,582 $ 97,563 $ 97,585 $ 92,002 $ 103,096 101 500 $ 1,289,419 $ 1,289,157 $ 1,122,910 $ 1,460,126 $ 156,117 $ 156,195 $ 147,245 $ 164,850 501 1,000 $ 1,175,129 $ 1,174,525 $ 1,040,001 $ 1,310,604 $ 117,149 $ 117,133 $ 110,736 $ 123,489 1,001 3,300 $ 1,882,416 $ 1,882,016 $ 1,627,291 $ 2,132,136 $ 116,179 $ 116,155 $ 109,677 $ 122,622 3,301 10K $ 1,298,277 $ 1,297,353 $ 1,138,788 $ 1,457,237 $ 74,216 $ 74,208 $ 69,715 $ 78,653 Small $ 6,343,313 $ 6,339,222 $ 5,565,009 $ 7,126,486 $ 561,223 $ 561,304 $ 529,983 $ 591,909 10,001 50K $ 2,925,044 $ 2,932,258 $ 2,517,316 $ 3,321,130 $ 87,174 $ 87,206 $ 82,498 $ 91,866 50,001 100K $ 929,875 $ 931,946 $ 799,054 $ 1,057,815 $ 23,823 $ 23,834 $ 22,464 $ 25,193 100,001 1M $ 1,474,696 $ 1,477,928 $ 1,271,453 $ 1,673,323 $ 39,520 $ 39,532 $ 37,288 $ 41,734 > 1 Million $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 Large $ 5,329,614 $ 5,340,937 $ 4,588,670 $ 6,052,713 $ 150,517 $ 150,573 $ 142,390 $ 158,714 NTNCWS Total $ 11,672,928 $ 11,679,476 $ 10,254,934 $ 13,049,966 $ 711,740 $ 711,676 $ 675,411 $ 747,580 TNCWSs < 100 $ 3,506,432 $ 3,508,973 $ 3,006,200 $ 4,003,903 $ 484,242 $ 484,063 $ 456,550 $ 512,039 101 500 $ 2,145,508 $ 2,146,536 $ 1,860,508 $ 2,430,946 $ 273,655 $ 273,537 $ 258,140 $ 289,187 501 1,000 $ 968,600 $ 968,547 $ 859,044 $ 1,079,246 $ 100,061 $ 100,027 $ 94,583 $ 105,572 1,001 3,300 $ 1,649,593 $ 1,649,939 $ 1,449,943 $ 1,851,294 $ 136,164 $ 136,119 $ 128,533 $ 143,756 3,301 10K $ 1,994,008 $ 1,994,205 $ 1,751,548 $ 2,239,512 $ 110,724 $ 110,710 $ 103,992 $ 117,358 Small $ 10,264,140 $ 10,264,853 $ 8,970,509 $ 11,558,708 $ 1,104,845 $ 1,104,453 $ 1,042,506 $ 1,166,696 10,001 50K $ 2,910,586 $ 2,909,729 $ 2,516,633 $ 3,303,385 $ 97,842 $ 97,874 $ 92,628 $ 103,135 50,001 100K $ 1,998,628 $ 1,997,407 $ 1,718,467 $ 2,276,530 $ 54,089 $ 54,102 $ 51,085 $ 57,087 100,001 1M $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 > 1 Million $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 Large $ 4,909,214 $ 4,905,638 $ 4,234,100 $ 5,581,299 $ 151,931 $ 151,968 $ 143,846 $ 160,167 TNCWS Total $ 15,173,354 $ 15,170,223 $ 13,464,218 $ 16,896,704 $ 1,256,777 $ 1,256,510 $ 1,189,344 $ 1,324,268 All Types < 100 $ 5,370,334 $ 5,375,002 $ 4,840,722 $ 5,890,324 $ 754,622 $ 754,293 $ 724,469 $ 785,042 101 500 $ 7,022,069 $ 7,022,159 $ 6,438,084 $ 7,604,054 $ 910,809 $ 910,439 $ 877,431 $ 944,980 501 1,000 $ 7,633,810 $ 7,635,000 $ 6,965,084 $ 8,311,884 $ 802,294 $ 802,228 $ 768,299 $ 836,750 1,001 3,300 $ 27,287,703 $ 27,282,608 $ 24,455,193 $ 30,188,898 $ 2,303,588 $ 2,303,189 $ 2,186,817 $ 2,420,537 3,301 10K $ 79,695,639 $ 79,709,111 $ 70,019,653 $ 89,542,947 $ 4,470,998 $ 4,471,081 $ 4,210,261 $ 4,732,502 Small $ 127,009,555 $ 126,996,280 $ 113,192,680 $ 141,029,856 $ 9,242,312 $ 9,241,714 $ 8,797,635 $ 9,691,740 10,001 50K $ 365,807,447 $ 366,020,777 $ 316,104,675 $ 414,979,459 $ 12,112,434 $ 12,112,880 $ 11,465,916 $ 12,759,530 50,001 100K $ 204,108,119 $ 204,200,022 $ 175,844,976 $ 232,062,648 $ 6,035,491 $ 6,035,626 $ 5,711,413 $ 6,357,405 100,001 1M $ 619,598,120 $ 619,752,017 $ 531,879,599 $ 706,183,129 $ 16,587,530 $ 16,594,245 $ 15,651,332 $ 17,506,424 > 1 Million $ 428,436,029 $ 428,643,237 $ 361,486,896 $ 494,697,645 $ 11,640,052 $ 11,644,134 $ 10,896,917 $ 12,371,585 Large $ 1,617,949,714 $ 1,618,382,674 $ 1,385,663,300 $ 1,847,720,957 $ 46,375,507 $ 46,393,329 $ 43,764,578 $ 48,948,091 All Sizes $ 1,744,959,269 $ 1,745,111,623 $ 1,502,408,880 $ 1,985,183,103 $ 55,617,819 $ 55,622,077 $ 52,779,574 $ 58,456,301 Notes: All values in year 2000 dollars.

Detail may not add exactly to totals due to independent rounding.

Derived from LT2ESWTR Cost Model. Median Value Mean Value Median Value Mean Value Economic Analysis for the LT2ESWTR Proposal Q 16 June 2003 Exhibit Q. 15 Treatment Capital and O& M Costs by System Size for Alternative 3  ICRSSL UV90 10 A3 ICRSSL UV90 10 Capital Costs O& M Costs 90 Percent Confidence Bound 90 Percent Confidence Bound System Classification System Size ( population served) Lower ( 5th % tile) Upper ( 95th % tile) Lower ( 5th % tile) Upper ( 95th % tile)

CWSs < 100 $ 889,403 $ 888,520 $ 742,789 $ 1,036,547 $ 115,160 $ 115,183 $ 107,916 $ 122,336 101 500 $ 2,625,777 $ 2,624,852 $ 2,216,711 $ 3,036,220 $ 319,705 $ 319,775 $ 299,002 $ 340,251 501 1,000 $ 3,621,498 $ 3,621,113 $ 3,139,040 $ 4,101,035 $ 385,679 $ 385,817 $ 363,706 $ 407,243 1,001 3,300 $ 15,683,695 $ 15,680,120 $ 13,549,259 $ 17,805,510 $ 1,363,245 $ 1,363,918 $ 1,276,844 $ 1,448,425 3,301 10K $ 50,563,496 $ 50,557,302 $ 43,462,461 $ 57,630,875 $ 3,041,893 $ 3,042,147 $ 2,816,714 $ 3,263,705 Small $ 73,383,869 $ 73,359,729 $ 63,120,696 $ 83,550,367 $ 5,225,682 $ 5,226,442 $ 4,868,895 $ 5,576,915 10,001 50K $ 251,726,669 $ 251,301,417 $ 215,579,318 $ 288,942,247 $ 8,176,978 $ 8,178,245 $ 7,724,923 $ 8,620,991 50,001 100K $ 137,756,856 $ 137,539,061 $ 117,331,799 $ 158,730,183 $ 3,807,439 $ 3,808,406 $ 3,605,748 $ 4,005,892 100,001 1M $ 413,095,729 $ 412,373,879 $ 350,954,952 $ 477,064,383 $ 9,698,950 $ 9,703,243 $ 9,232,786 $ 10,162,621 > 1 Million $ 323,756,756 $ 323,217,020 $ 270,638,061 $ 378,606,767 $ 7,879,221 $ 7,883,304 $ 7,412,586 $ 8,345,794 Large $ 1,126,336,011 $ 1,124,477,998 $ 954,505,469 $ 1,303,276,866 $ 29,562,589 $ 29,574,423 $ 27,988,099 $ 31,121,610 CWS Total $ 1,199,719,880 $ 1,197,726,085 $ 1,022,027,822 $ 1,381,852,704 $ 34,788,271 $ 34,798,399 $ 33,041,523 $ 36,514,195 NTNCWSs < 100 $ 531,487 $ 531,739 $ 443,384 $ 619,756 $ 63,824 $ 63,827 $ 59,905 $ 67,710 101 500 $ 923,978 $ 924,507 $ 783,891 $ 1,064,781 $ 99,950 $ 99,945 $ 93,749 $ 106,139 501 1,000 $ 721,998 $ 722,419 $ 628,650 $ 816,790 $ 70,331 $ 70,358 $ 66,500 $ 74,099 1,001 3,300 $ 1,019,195 $ 1,018,037 $ 880,589 $ 1,160,297 $ 72,683 $ 72,683 $ 68,307 $ 77,023 3,301 10K $ 811,093 $ 811,606 $ 698,169 $ 925,494 $ 50,488 $ 50,485 $ 46,754 $ 54,213 Small $ 4,007,750 $ 4,009,141 $ 3,442,305 $ 4,575,406 $ 357,276 $ 357,237 $ 335,681 $ 378,691 10,001 50K $ 1,974,742 $ 1,979,795 $ 1,676,337 $ 2,263,805 $ 55,926 $ 55,933 $ 52,909 $ 58,897 50,001 100K $ 603,858 $ 605,267 $ 508,829 $ 695,797 $ 13,350 $ 13,347 $ 12,662 $ 14,033 100,001 1M $ 944,726 $ 946,907 $ 800,088 $ 1,085,268 $ 21,939 $ 21,935 $ 20,911 $ 22,950 > 1 Million $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 Large $ 3,523,326 $ 3,531,542 $ 2,984,420 $ 4,045,964 $ 91,214 $ 91,213 $ 86,511 $ 95,867 NTNCWS Total $ 7,531,076 $ 7,527,344 $ 6,603,346 $ 8,443,425 $ 448,491 $ 448,538 $ 424,115 $ 472,861 TNCWSs < 100 $ 2,682,748 $ 2,681,183 $ 2,235,450 $ 3,125,248 $ 315,762 $ 315,756 $ 296,267 $ 335,253 101 500 $ 1,569,750 $ 1,569,981 $ 1,324,681 $ 1,814,953 $ 175,592 $ 175,608 $ 164,581 $ 186,617 501 1,000 $ 602,195 $ 602,411 $ 524,419 $ 681,175 $ 60,390 $ 60,391 $ 57,143 $ 63,659 1,001 3,300 $ 981,663 $ 981,620 $ 841,627 $ 1,124,996 $ 86,428 $ 86,404 $ 80,940 $ 91,955 3,301 10K $ 1,248,202 $ 1,248,100 $ 1,075,594 $ 1,423,328 $ 75,594 $ 75,561 $ 70,029 $ 81,212 Small $ 7,084,559 $ 7,086,123 $ 6,009,933 $ 8,164,217 $ 713,766 $ 713,638 $ 669,695 $ 758,066 10,001 50K $ 1,971,809 $ 1,972,766 $ 1,683,229 $ 2,259,728 $ 64,901 $ 64,877 $ 61,395 $ 68,393 50,001 100K $ 1,309,918 $ 1,310,749 $ 1,106,068 $ 1,511,952 $ 31,391 $ 31,390 $ 29,781 $ 32,993 100,001 1M $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 > 1 Million $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 Large $ 3,281,727 $ 3,283,901 $ 2,789,270 $ 3,771,784 $ 96,292 $ 96,287 $ 91,162 $ 101,356 TNCWS Total $ 10,366,285 $ 10,371,507 $ 9,079,437 $ 11,680,526 $ 810,058 $ 810,090 $ 763,230 $ 856,980 All Types < 100 $ 4,103,638 $ 4,101,663 $ 3,628,130 $ 4,578,589 $ 494,746 $ 494,807 $ 473,341 $ 516,221 101 500 $ 5,119,506 $ 5,118,730 $ 4,623,864 $ 5,618,152 $ 595,247 $ 595,141 $ 570,616 $ 620,095 501 1,000 $ 4,945,691 $ 4,945,810 $ 4,445,467 $ 5,441,555 $ 516,400 $ 516,417 $ 493,671 $ 538,854 1,001 3,300 $ 17,684,552 $ 17,685,148 $ 15,523,137 $ 19,823,597 $ 1,522,356 $ 1,522,914 $ 1,435,226 $ 1,607,354 3,301 10K $ 52,622,791 $ 52,620,260 $ 45,496,935 $ 59,705,941 $ 3,167,976 $ 3,168,008 $ 2,942,302 $ 3,388,734 Small $ 84,476,178 $ 84,506,525 $ 74,079,551 $ 94,767,150 $ 6,296,725 $ 6,297,600 $ 5,935,997 $ 6,651,649 10,001 50K $ 255,673,221 $ 255,242,080 $ 219,447,014 $ 292,905,860 $ 8,297,805 $ 8,298,995 $ 7,844,470 $ 8,740,838 50,001 100K $ 139,670,632 $ 139,439,926 $ 119,210,080 $ 160,648,709 $ 3,852,180 $ 3,853,145 $ 3,650,965 $ 4,050,493 100,001 1M $ 414,040,455 $ 413,337,540 $ 351,874,060 $ 478,013,730 $ 9,720,889 $ 9,725,152 $ 9,254,718 $ 10,184,481 > 1 Million $ 323,756,756 $ 323,217,020 $ 270,638,061 $ 378,606,767 $ 7,879,221 $ 7,883,304 $ 7,412,586 $ 8,345,794 Large $ 1,133,141,064 $ 1,131,256,966 $ 961,489,067 $ 1,310,329,529 $ 29,750,095 $ 29,761,589 $ 28,175,518 $ 31,308,606 All Sizes $ 1,217,617,242 $ 1,215,685,307 $ 1,040,049,713 $ 1,399,786,498 $ 36,046,820 $ 36,054,960 $ 34,295,490 $ 37,769,288 Notes: All values in year 2000 dollars.

Detail may not add exactly to totals due to independent rounding.

Derived from LT2ESWTR Cost Model. Median Value Mean Value Median Value Mean Value Economic Analysis for the LT2ESWTR Proposal Q 17 June 2003 Exhibit Q. 16 Treatment Capital and O& M Costs by System Size for Alternative 3  ICRSSL UV90 10B A3 ICRSSL UV90 10B Capital Costs O& M Costs 90 Percent Confidence Bound 90 Percent Confidence Bound System Classification System Size ( population served) Lower ( 5th % tile) Upper ( 95th % tile) Lower ( 5th % tile) Upper ( 95th % tile)

CWSs < 100 $ 889,251 $ 888,858 $ 741,742 $ 1,035,543 $ 115,047 $ 115,057 $ 107,786 $ 122,321 101 500 $ 2,626,083 $ 2,626,048 $ 2,215,750 $ 3,036,646 $ 319,389 $ 319,420 $ 298,660 $ 340,147 501 1,000 $ 3,725,731 $ 3,724,266 $ 3,243,954 $ 4,210,822 $ 380,630 $ 380,648 $ 358,905 $ 402,240 1,001 3,300 $ 16,068,506 $ 16,059,970 $ 13,937,259 $ 18,218,443 $ 1,362,196 $ 1,362,021 $ 1,276,798 $ 1,447,676 3,301 10K $ 51,661,815 $ 51,647,396 $ 44,572,244 $ 58,835,030 $ 3,077,017 $ 3,076,246 $ 2,857,546 $ 3,297,786 Small $ 74,971,386 $ 74,937,859 $ 64,736,615 $ 85,308,406 $ 5,254,280 $ 5,252,674 $ 4,904,388 $ 5,605,544 10,001 50K $ 265,444,475 $ 265,639,707 $ 227,610,258 $ 302,961,087 $ 8,746,144 $ 8,746,213 $ 8,276,839 $ 9,213,326 50,001 100K $ 146,808,739 $ 146,893,908 $ 125,478,325 $ 168,085,154 $ 4,216,698 $ 4,216,590 $ 3,997,885 $ 4,436,605 100,001 1M $ 444,564,823 $ 444,776,107 $ 378,819,577 $ 509,785,699 $ 11,190,500 $ 11,193,230 $ 10,624,617 $ 11,754,358 > 1 Million $ 340,723,276 $ 340,889,357 $ 285,204,229 $ 395,790,556 $ 8,730,231 $ 8,733,400 $ 8,195,573 $ 9,260,754 Large $ 1,197,541,313 $ 1,198,134,846 $ 1,017,545,589 $ 1,376,733,908 $ 32,883,573 $ 32,886,659 $ 31,117,131 $ 34,642,084 CWS Total $ 1,272,512,699 $ 1,272,841,610 $ 1,087,056,229 $ 1,457,948,282 $ 38,137,853 $ 38,137,351 $ 36,203,024 $ 40,065,546 NTNCWSs < 100 $ 531,487 $ 531,739 $ 443,384 $ 619,756 $ 63,824 $ 63,827 $ 59,905 $ 67,710 101 500 $ 923,978 $ 924,507 $ 783,891 $ 1,064,781 $ 99,950 $ 99,945 $ 93,749 $ 106,139 501 1,000 $ 745,320 $ 746,062 $ 650,798 $ 840,221 $ 69,167 $ 69,173 $ 65,427 $ 72,892 1,001 3,300 $ 1,072,382 $ 1,071,735 $ 932,397 $ 1,213,062 $ 72,431 $ 72,415 $ 68,044 $ 76,754 3,301 10K $ 832,318 $ 832,773 $ 719,210 $ 946,835 $ 51,249 $ 51,250 $ 47,507 $ 54,987 Small $ 4,105,485 $ 4,105,461 $ 3,542,220 $ 4,676,137 $ 356,621 $ 356,568 $ 334,937 $ 378,077 10,001 50K $ 2,087,077 $ 2,091,739 $ 1,784,918 $ 2,380,591 $ 60,902 $ 60,894 $ 57,702 $ 64,094 50,001 100K $ 651,504 $ 653,247 $ 555,395 $ 744,724 $ 15,542 $ 15,549 $ 14,733 $ 16,354 100,001 1M $ 1,020,627 $ 1,023,296 $ 873,096 $ 1,163,590 $ 25,587 $ 25,594 $ 24,334 $ 26,851 > 1 Million $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 Large $ 3,759,207 $ 3,769,133 $ 3,213,840 $ 4,289,679 $ 102,030 $ 102,041 $ 96,822 $ 107,248 NTNCWS Total $ 7,864,692 $ 7,864,019 $ 6,933,547 $ 8,794,921 $ 458,652 $ 458,566 $ 434,229 $ 483,043 TNCWSs < 100 $ 2,676,058 $ 2,676,927 $ 2,229,632 $ 3,117,570 $ 316,113 $ 315,923 $ 296,577 $ 335,390 101 500 $ 1,566,029 $ 1,566,835 $ 1,319,837 $ 1,809,339 $ 175,791 $ 175,747 $ 164,716 $ 186,671 501 1,000 $ 621,079 $ 621,301 $ 542,649 $ 700,259 $ 59,511 $ 59,501 $ 56,294 $ 62,702 1,001 3,300 $ 1,042,129 $ 1,042,311 $ 900,365 $ 1,183,156 $ 86,937 $ 86,927 $ 81,481 $ 92,300 3,301 10K $ 1,278,314 $ 1,279,208 $ 1,105,599 $ 1,452,592 $ 76,862 $ 76,919 $ 71,321 $ 82,401 Small $ 7,183,609 $ 7,187,131 $ 6,112,715 $ 8,255,124 $ 715,213 $ 715,088 $ 670,667 $ 758,628 10,001 50K $ 2,079,519 $ 2,078,434 $ 1,786,358 $ 2,370,785 $ 69,656 $ 69,691 $ 65,962 $ 73,388 50,001 100K $ 1,406,847 $ 1,406,689 $ 1,201,030 $ 1,611,918 $ 35,965 $ 35,976 $ 34,125 $ 37,828 100,001 1M $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 > 1 Million $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 Large $ 3,486,366 $ 3,484,528 $ 2,986,945 $ 3,982,004 $ 105,621 $ 105,653 $ 100,136 $ 111,164 TNCWS Total $ 10,669,976 $ 10,672,679 $ 9,375,286 $ 11,968,578 $ 820,834 $ 820,619 $ 773,640 $ 867,487 All Types < 100 $ 4,096,796 $ 4,101,189 $ 3,624,884 $ 4,566,672 $ 494,985 $ 494,806 $ 473,842 $ 516,112 101 500 $ 5,116,090 $ 5,118,246 $ 4,617,790 $ 5,608,899 $ 595,130 $ 595,067 $ 570,724 $ 619,809 501 1,000 $ 5,092,130 $ 5,092,673 $ 4,587,430 $ 5,596,639 $ 509,308 $ 509,344 $ 487,101 $ 531,640 1,001 3,300 $ 18,183,017 $ 18,186,889 $ 16,027,511 $ 20,330,381 $ 1,521,564 $ 1,521,524 $ 1,436,390 $ 1,607,402 3,301 10K $ 53,772,447 $ 53,754,291 $ 46,684,452 $ 60,930,157 $ 3,205,128 $ 3,204,313 $ 2,985,555 $ 3,426,295 Small $ 86,260,481 $ 86,288,382 $ 75,875,119 $ 96,620,720 $ 6,326,114 $ 6,326,252 $ 5,971,485 $ 6,682,779 10,001 50K $ 269,611,071 $ 269,722,302 $ 231,796,327 $ 307,102,412 $ 8,876,703 $ 8,876,271 $ 8,408,416 $ 9,345,472 50,001 100K $ 148,867,090 $ 148,930,402 $ 127,527,864 $ 170,168,175 $ 4,268,205 $ 4,267,881 $ 4,049,153 $ 4,488,237 100,001 1M $ 445,585,450 $ 445,817,320 $ 379,846,830 $ 510,841,400 $ 11,216,087 $ 11,218,356 $ 10,650,584 $ 11,779,892 > 1 Million $ 340,723,276 $ 340,889,357 $ 285,204,229 $ 395,790,556 $ 8,730,231 $ 8,733,400 $ 8,195,573 $ 9,260,754 Large $ 1,204,786,886 $ 1,205,286,301 $ 1,024,459,222 $ 1,383,938,431 $ 33,091,225 $ 33,093,913 $ 31,323,176 $ 34,849,243 All Sizes $ 1,291,047,367 $ 1,291,304,793 $ 1,105,516,667 $ 1,476,316,000 $ 39,417,338 $ 39,411,760 $ 37,484,930 $ 41,346,544 Notes: All values in year 2000 dollars.

Detail may not add exactly to totals due to independent rounding.

Derived from LT2ESWTR Cost Model. Median Value Mean Value Median Value Mean Value Economic Analysis for the LT2ESWTR Proposal Q 18 June 2003 Exhibit Q. 17 Treatment Capital and O& M Costs by System Size for Alternative 3  ICRSSM UV90 10 A3 ICRSSM UV90 10 Capital Costs O& M Costs 90 Percent Confidence Bound 90 Percent Confidence Bound System Classification System Size ( population served) Lower ( 5th % tile) Upper ( 95th % tile) Lower ( 5th % tile) Upper ( 95th % tile)

CWSs < 100 $ 729,809 $ 729,042 $ 604,878 $ 855,657 $ 92,392 $ 92,420 $ 86,318 $ 98,389 101 500 $ 2,144,089 $ 2,143,498 $ 1,789,976 $ 2,496,511 $ 257,524 $ 257,582 $ 239,966 $ 274,897 501 1,000 $ 2,962,704 $ 2,960,951 $ 2,548,627 $ 3,376,439 $ 309,323 $ 309,430 $ 290,929 $ 327,386 1,001 3,300 $ 12,737,829 $ 12,728,715 $ 10,913,574 $ 14,561,948 $ 1,092,074 $ 1,092,211 $ 1,018,785 $ 1,164,395 3,301 10K $ 41,321,756 $ 41,314,852 $ 35,238,535 $ 47,387,407 $ 2,503,892 $ 2,504,342 $ 2,308,219 $ 2,697,727 Small $ 59,896,186 $ 59,868,812 $ 51,103,407 $ 68,662,563 $ 4,255,206 $ 4,255,420 $ 3,947,561 $ 4,558,872 10,001 50K $ 206,955,387 $ 206,568,287 $ 176,968,842 $ 237,725,378 $ 6,708,977 $ 6,709,253 $ 6,334,994 $ 7,078,194 50,001 100K $ 112,918,530 $ 112,734,765 $ 96,006,628 $ 130,225,795 $ 3,098,777 $ 3,099,287 $ 2,932,182 $ 3,263,495 100,001 1M $ 338,833,828 $ 338,254,844 $ 287,412,010 $ 391,804,818 $ 7,854,351 $ 7,858,822 $ 7,468,401 $ 8,237,735 > 1 Million $ 286,934,447 $ 286,494,250 $ 239,424,215 $ 335,975,879 $ 6,960,770 $ 6,964,784 $ 6,536,059 $ 7,385,978 Large $ 945,642,191 $ 944,034,414 $ 800,066,210 $ 1,095,544,444 $ 24,622,875 $ 24,628,243 $ 23,276,356 $ 25,954,188 CWS Total $ 1,005,538,378 $ 1,003,827,534 $ 855,099,069 $ 1,159,438,238 $ 28,878,081 $ 28,883,870 $ 27,399,979 $ 30,337,798 NTNCWSs < 100 $ 434,875 $ 435,044 $ 359,547 $ 510,139 $ 50,681 $ 50,676 $ 47,463 $ 53,880 101 500 $ 745,162 $ 745,730 $ 626,410 $ 865,263 $ 78,384 $ 78,370 $ 73,292 $ 83,462 501 1,000 $ 563,584 $ 563,811 $ 486,235 $ 641,764 $ 52,603 $ 52,611 $ 49,648 $ 55,530 1,001 3,300 $ 763,310 $ 763,178 $ 658,018 $ 871,623 $ 55,633 $ 55,629 $ 52,055 $ 59,192 3,301 10K $ 633,433 $ 634,077 $ 540,182 $ 727,871 $ 40,190 $ 40,187 $ 37,022 $ 43,371 Small $ 3,140,364 $ 3,142,564 $ 2,675,124 $ 3,612,830 $ 277,490 $ 277,387 $ 259,737 $ 295,095 10,001 50K $ 1,597,738 $ 1,601,640 $ 1,354,956 $ 1,833,920 $ 44,985 $ 44,989 $ 42,522 $ 47,423 50,001 100K $ 487,484 $ 488,566 $ 410,162 $ 562,380 $ 10,586 $ 10,585 $ 10,030 $ 11,136 100,001 1M $ 760,885 $ 762,581 $ 643,566 $ 874,896 $ 17,391 $ 17,387 $ 16,566 $ 18,202 > 1 Million $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 Large $ 2,846,107 $ 2,853,071 $ 2,408,183 $ 3,269,734 $ 72,961 $ 72,962 $ 69,150 $ 76,746 NTNCWS Total $ 5,986,471 $ 5,983,013 $ 5,248,074 $ 6,718,694 $ 350,452 $ 350,433 $ 330,857 $ 370,009 TNCWSs < 100 $ 2,196,136 $ 2,195,506 $ 1,813,511 $ 2,577,345 $ 250,705 $ 250,682 $ 234,665 $ 266,776 101 500 $ 1,270,829 $ 1,271,407 $ 1,062,486 $ 1,478,826 $ 137,990 $ 137,984 $ 128,929 $ 147,119 501 1,000 $ 472,081 $ 472,266 $ 407,786 $ 537,440 $ 45,301 $ 45,301 $ 42,748 $ 47,854 1,001 3,300 $ 768,614 $ 769,488 $ 652,927 $ 885,580 $ 66,867 $ 66,841 $ 62,371 $ 71,403 3,301 10K $ 974,819 $ 975,043 $ 832,670 $ 1,118,952 $ 60,278 $ 60,242 $ 55,564 $ 65,059 Small $ 5,682,479 $ 5,684,693 $ 4,768,608 $ 6,591,886 $ 561,139 $ 561,142 $ 524,864 $ 597,633 10,001 50K $ 1,595,630 $ 1,596,472 $ 1,360,454 $ 1,830,189 $ 52,423 $ 52,404 $ 49,555 $ 55,271 50,001 100K $ 1,058,253 $ 1,058,867 $ 892,327 $ 1,223,391 $ 25,001 $ 24,998 $ 23,691 $ 26,292 100,001 1M $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 > 1 Million $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 Large $ 2,653,883 $ 2,654,756 $ 2,253,357 $ 3,053,074 $ 77,424 $ 77,401 $ 73,254 $ 81,561 TNCWS Total $ 8,336,363 $ 8,339,311 $ 7,273,380 $ 9,415,386 $ 638,564 $ 638,561 $ 600,196 $ 677,071 All Types < 100 $ 3,360,820 $ 3,357,905 $ 2,953,691 $ 3,766,042 $ 393,779 $ 393,842 $ 376,180 $ 411,452 101 500 $ 4,160,080 $ 4,159,269 $ 3,731,578 $ 4,588,707 $ 473,898 $ 473,816 $ 453,056 $ 494,600 501 1,000 $ 3,998,369 $ 3,994,808 $ 3,570,062 $ 4,422,243 $ 407,226 $ 407,242 $ 388,063 $ 426,036 1,001 3,300 $ 14,269,753 $ 14,262,440 $ 12,433,450 $ 16,092,929 $ 1,214,574 $ 1,214,773 $ 1,140,896 $ 1,287,143 3,301 10K $ 42,930,008 $ 42,914,214 $ 36,837,634 $ 48,983,793 $ 2,604,359 $ 2,604,590 $ 2,408,872 $ 2,797,372 Small $ 68,719,029 $ 68,695,151 $ 59,890,155 $ 77,529,576 $ 5,093,835 $ 5,093,916 $ 4,784,095 $ 5,400,193 10,001 50K $ 210,148,755 $ 209,754,274 $ 180,179,460 $ 240,908,284 $ 6,806,385 $ 6,807,208 $ 6,432,760 $ 7,175,628 50,001 100K $ 114,464,268 $ 114,280,895 $ 97,558,648 $ 131,790,344 $ 3,134,364 $ 3,134,908 $ 2,967,632 $ 3,299,039 100,001 1M $ 339,594,713 $ 339,033,489 $ 288,124,784 $ 392,522,966 $ 7,871,742 $ 7,876,011 $ 7,485,931 $ 8,255,154 > 1 Million $ 286,934,447 $ 286,494,250 $ 239,424,215 $ 335,975,879 $ 6,960,770 $ 6,964,784 $ 6,536,059 $ 7,385,978 Large $ 951,142,182 $ 949,474,439 $ 805,612,690 $ 1,101,188,629 $ 24,773,261 $ 24,778,617 $ 23,426,866 $ 26,105,601 All Sizes $ 1,019,861,212 $ 1,018,066,534 $ 869,351,393 $ 1,173,895,633 $ 29,867,096 $ 29,871,890 $ 28,391,086 $ 31,327,718 Notes: All values in year 2000 dollars.

Detail may not add exactly to totals due to independent rounding.

Derived from LT2ESWTR Cost Model. Median Value Mean Value Median Value Mean Value Economic Analysis for the LT2ESWTR Proposal Q 19 June 2003 Exhibit Q. 18 Treatment Capital and O& M Costs by System Size for Alternative 3  ICRSSM UV90 10B A3 ICRSSM UV90 10B Capital Costs O& M Costs 90 Percent Confidence Bound 90 Percent Confidence Bound System Classification System Size ( population served) Lower ( 5th % tile) Upper ( 95th % tile) Lower ( 5th % tile) Upper ( 95th % tile)

CWSs < 100 $ 729,692 $ 729,573 $ 603,649 $ 855,428 $ 92,302 $ 92,301 $ 86,249 $ 98,403 101 500 $ 2,144,424 $ 2,145,235 $ 1,791,793 $ 2,497,747 $ 257,275 $ 257,265 $ 239,755 $ 274,902 501 1,000 $ 3,034,604 $ 3,033,481 $ 2,621,940 $ 3,447,931 $ 307,235 $ 307,291 $ 289,098 $ 325,331 1,001 3,300 $ 13,004,918 $ 13,004,565 $ 11,184,870 $ 14,831,170 $ 1,094,454 $ 1,094,255 $ 1,022,563 $ 1,166,542 3,301 10K $ 42,053,818 $ 42,047,393 $ 35,965,808 $ 48,174,218 $ 2,531,114 $ 2,529,929 $ 2,341,108 $ 2,722,083 Small $ 60,967,456 $ 60,946,826 $ 52,192,494 $ 69,784,730 $ 4,282,379 $ 4,280,930 $ 3,981,698 $ 4,583,482 10,001 50K $ 216,277,878 $ 216,403,582 $ 185,086,320 $ 247,219,627 $ 7,116,273 $ 7,117,007 $ 6,731,087 $ 7,498,662 50,001 100K $ 119,082,655 $ 119,187,592 $ 101,567,989 $ 136,555,634 $ 3,390,962 $ 3,391,070 $ 3,214,224 $ 3,567,460 100,001 1M $ 359,926,787 $ 360,133,270 $ 306,251,650 $ 413,398,349 $ 8,894,575 $ 8,895,711 $ 8,451,396 $ 9,338,005 > 1 Million $ 298,378,964 $ 298,575,012 $ 248,732,624 $ 347,464,750 $ 7,548,891 $ 7,550,777 $ 7,084,552 $ 8,011,524 Large $ 993,666,284 $ 994,376,209 $ 841,997,310 $ 1,144,951,316 $ 26,950,701 $ 26,953,830 $ 25,498,421 $ 28,403,322 CWS Total $ 1,054,633,740 $ 1,054,999,754 $ 898,775,829 $ 1,210,237,142 $ 31,233,080 $ 31,233,307 $ 29,652,311 $ 32,815,133 NTNCWSs < 100 $ 434,875 $ 435,044 $ 359,547 $ 510,139 $ 50,681 $ 50,676 $ 47,463 $ 53,880 101 500 $ 745,162 $ 745,730 $ 626,410 $ 865,263 $ 78,384 $ 78,370 $ 73,292 $ 83,462 501 1,000 $ 579,609 $ 580,188 $ 502,019 $ 658,054 $ 52,145 $ 52,135 $ 49,251 $ 55,031 1,001 3,300 $ 798,004 $ 797,548 $ 691,924 $ 906,375 $ 55,691 $ 55,684 $ 52,117 $ 59,237 3,301 10K $ 647,606 $ 648,216 $ 554,048 $ 742,121 $ 40,779 $ 40,776 $ 37,614 $ 43,954 Small $ 3,205,255 $ 3,207,458 $ 2,739,015 $ 3,677,452 $ 277,680 $ 277,579 $ 259,930 $ 295,315 10,001 50K $ 1,672,610 $ 1,676,529 $ 1,427,803 $ 1,910,841 $ 48,519 $ 48,509 $ 45,956 $ 51,054 50,001 100K $ 519,362 $ 520,602 $ 441,432 $ 595,138 $ 12,121 $ 12,124 $ 11,495 $ 12,746 100,001 1M $ 810,799 $ 812,573 $ 691,790 $ 926,201 $ 19,912 $ 19,920 $ 18,956 $ 20,863 > 1 Million $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 Large $ 3,002,771 $ 3,009,111 $ 2,560,742 $ 3,431,469 $ 80,551 $ 80,548 $ 76,449 $ 84,631 NTNCWS Total $ 6,208,027 $ 6,207,252 $ 5,465,953 $ 6,943,415 $ 358,232 $ 358,160 $ 338,554 $ 377,820 TNCWSs < 100 $ 2,190,379 $ 2,190,869 $ 1,808,236 $ 2,568,491 $ 250,997 $ 250,881 $ 234,971 $ 266,875 101 500 $ 1,267,629 $ 1,268,133 $ 1,059,353 $ 1,474,610 $ 138,156 $ 138,114 $ 129,024 $ 147,111 501 1,000 $ 484,943 $ 485,031 $ 420,055 $ 550,161 $ 44,987 $ 44,981 $ 42,467 $ 47,478 1,001 3,300 $ 807,618 $ 807,679 $ 691,850 $ 924,150 $ 67,435 $ 67,460 $ 62,943 $ 71,882 3,301 10K $ 994,527 $ 994,767 $ 852,630 $ 1,137,815 $ 61,256 $ 61,281 $ 56,514 $ 65,945 Small $ 5,745,096 $ 5,746,463 $ 4,837,934 $ 6,647,842 $ 562,831 $ 562,852 $ 526,623 $ 598,468 10,001 50K $ 1,667,189 $ 1,666,334 $ 1,430,320 $ 1,903,323 $ 55,802 $ 55,826 $ 52,834 $ 58,787 50,001 100K $ 1,123,049 $ 1,122,539 $ 955,560 $ 1,288,945 $ 28,221 $ 28,227 $ 26,790 $ 29,670 100,001 1M $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 > 1 Million $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 Large $ 2,790,238 $ 2,789,245 $ 2,385,502 $ 3,192,133 $ 84,023 $ 84,059 $ 79,645 $ 88,462 TNCWS Total $ 8,535,334 $ 8,536,787 $ 7,460,519 $ 9,604,891 $ 646,854 $ 646,717 $ 608,679 $ 684,427 All Types < 100 $ 3,354,946 $ 3,357,958 $ 2,953,326 $ 3,755,972 $ 393,980 $ 393,834 $ 376,512 $ 411,367 101 500 $ 4,157,215 $ 4,159,059 $ 3,730,065 $ 4,579,437 $ 473,814 $ 473,787 $ 453,338 $ 494,446 501 1,000 $ 4,099,156 $ 4,100,465 $ 3,668,311 $ 4,525,683 $ 404,368 $ 404,364 $ 385,716 $ 422,960 1,001 3,300 $ 14,610,539 $ 14,614,187 $ 12,773,741 $ 16,439,985 $ 1,217,581 $ 1,217,413 $ 1,145,356 $ 1,290,244 3,301 10K $ 43,695,951 $ 43,706,132 $ 37,588,623 $ 49,820,215 $ 2,633,149 $ 2,632,139 $ 2,443,218 $ 2,825,071 Small $ 69,917,807 $ 69,955,352 $ 61,030,294 $ 78,741,056 $ 5,122,891 $ 5,122,222 $ 4,818,884 $ 5,429,060 10,001 50K $ 219,617,677 $ 219,764,833 $ 188,454,371 $ 250,547,502 $ 7,220,594 $ 7,221,217 $ 6,835,099 $ 7,603,996 50,001 100K $ 120,725,066 $ 120,812,247 $ 103,212,761 $ 138,183,875 $ 3,431,304 $ 3,431,443 $ 3,254,689 $ 3,607,943 100,001 1M $ 360,737,587 $ 360,936,911 $ 307,082,781 $ 414,201,991 $ 8,914,487 $ 8,915,303 $ 8,471,571 $ 9,357,626 > 1 Million $ 298,378,964 $ 298,575,012 $ 248,732,624 $ 347,464,750 $ 7,548,891 $ 7,550,777 $ 7,084,552 $ 8,011,524 Large $ 999,459,294 $ 1,000,157,923 $ 847,811,732 $ 1,150,553,963 $ 27,115,275 $ 27,118,329 $ 25,663,182 $ 28,567,485 All Sizes $ 1,069,377,101 $ 1,069,588,481 $ 913,637,163 $ 1,225,011,340 $ 32,238,166 $ 32,240,748 $ 30,657,060 $ 33,815,180 Notes: All values in year 2000 dollars.

Detail may not add exactly to totals due to independent rounding.

Derived from LT2ESWTR Cost Model. Median Value Mean Value Median Value Mean Value Economic Analysis for the LT2ESWTR Proposal Q 20 June 2003 Exhibit Q. 19 Treatment Capital and O& M Costs by System Size for Alternative 3  High UV90 10 A3 High UV90 10 Capital Costs O& M Costs 90 Percent Confidence Bound 90 Percent Confidence Bound System Classification System Size ( population served) Lower ( 5th % tile) Upper ( 95th % tile) Lower ( 5th % tile) Upper ( 95th % tile)

CWSs < 100 $ 1,284,649 $ 1,284,398 $ 1,101,166 $ 1,469,469 $ 187,550 $ 187,540 $ 176,679 $ 198,431 101 500 $ 3,922,629 $ 3,920,802 $ 3,393,884 $ 4,451,589 $ 519,643 $ 519,700 $ 489,079 $ 549,926 501 1,000 $ 5,637,223 $ 5,637,968 $ 4,952,006 $ 6,311,514 $ 649,394 $ 649,536 $ 613,992 $ 684,156 1,001 3,300 $ 24,615,054 $ 24,629,150 $ 21,560,450 $ 27,631,195 $ 2,236,375 $ 2,236,649 $ 2,108,867 $ 2,361,655 3,301 10K $ 79,013,193 $ 79,027,892 $ 68,628,425 $ 89,307,234 $ 4,580,253 $ 4,581,769 $ 4,292,333 $ 4,862,991 Small $ 114,472,748 $ 114,517,127 $ 99,739,295 $ 129,045,277 $ 8,173,216 $ 8,175,299 $ 7,692,948 $ 8,647,552 10,001 50K $ 364,148,307 $ 363,490,742 $ 313,023,629 $ 416,853,363 $ 11,927,595 $ 11,933,997 $ 11,292,492 $ 12,552,115 50,001 100K $ 200,535,409 $ 200,163,454 $ 171,526,420 $ 230,354,754 $ 5,691,103 $ 5,692,779 $ 5,400,758 $ 5,977,947 100,001 1M $ 603,955,330 $ 602,693,177 $ 515,595,565 $ 694,928,924 $ 14,862,281 $ 14,867,698 $ 14,163,599 $ 15,557,151 > 1 Million $ 418,660,846 $ 417,861,281 $ 351,835,994 $ 487,351,873 $ 10,534,917 $ 10,539,580 $ 9,944,657 $ 11,124,271 Large $ 1,587,299,893 $ 1,584,218,156 $ 1,352,178,491 $ 1,829,517,330 $ 43,015,898 $ 43,022,761 $ 40,823,445 $ 45,192,071 CWS Total $ 1,701,772,641 $ 1,698,596,723 $ 1,455,616,199 $ 1,954,652,509 $ 51,189,113 $ 51,201,845 $ 48,701,256 $ 53,679,307 NTNCWSs < 100 $ 770,042 $ 769,566 $ 659,330 $ 881,302 $ 105,954 $ 105,987 $ 99,907 $ 111,970 101 500 $ 1,413,523 $ 1,413,232 $ 1,228,755 $ 1,602,502 $ 169,294 $ 169,377 $ 159,655 $ 178,816 501 1,000 $ 1,212,615 $ 1,212,098 $ 1,069,852 $ 1,356,470 $ 132,116 $ 132,113 $ 125,184 $ 138,972 1,001 3,300 $ 1,870,532 $ 1,868,520 $ 1,600,068 $ 2,136,812 $ 128,403 $ 128,429 $ 121,403 $ 135,391 3,301 10K $ 1,350,333 $ 1,349,066 $ 1,179,635 $ 1,523,127 $ 79,732 $ 79,722 $ 74,761 $ 84,633 Small $ 6,617,045 $ 6,609,815 $ 5,776,123 $ 7,471,014 $ 615,499 $ 615,700 $ 581,641 $ 649,167 10,001 50K $ 2,950,479 $ 2,957,510 $ 2,514,391 $ 3,373,142 $ 85,285 $ 85,280 $ 80,859 $ 89,683 50,001 100K $ 909,511 $ 911,668 $ 770,817 $ 1,044,004 $ 21,324 $ 21,328 $ 20,275 $ 22,373 100,001 1M $ 1,433,128 $ 1,436,085 $ 1,218,185 $ 1,640,826 $ 35,106 $ 35,104 $ 33,494 $ 36,701 > 1 Million $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 Large $ 5,293,118 $ 5,306,588 $ 4,504,635 $ 6,058,526 $ 141,715 $ 141,697 $ 134,673 $ 148,705 NTNCWS Total $ 11,910,163 $ 11,903,638 $ 10,407,882 $ 13,373,410 $ 757,214 $ 757,249 $ 718,356 $ 795,821 TNCWSs < 100 $ 3,877,135 $ 3,875,804 $ 3,319,810 $ 4,433,641 $ 525,265 $ 525,030 $ 495,106 $ 555,807 101 500 $ 2,361,129 $ 2,361,486 $ 2,042,813 $ 2,680,367 $ 296,537 $ 296,417 $ 279,609 $ 313,507 501 1,000 $ 1,000,278 $ 1,000,559 $ 882,682 $ 1,119,279 $ 112,610 $ 112,601 $ 106,681 $ 118,537 1,001 3,300 $ 1,610,495 $ 1,610,847 $ 1,394,382 $ 1,828,475 $ 148,298 $ 148,290 $ 139,993 $ 156,576 3,301 10K $ 2,077,549 $ 2,078,271 $ 1,813,067 $ 2,345,566 $ 118,755 $ 118,718 $ 111,394 $ 126,241 Small $ 10,926,586 $ 10,924,528 $ 9,499,900 $ 12,371,558 $ 1,201,466 $ 1,201,100 $ 1,133,788 $ 1,269,741 10,001 50K $ 2,944,414 $ 2,945,515 $ 2,521,273 $ 3,362,353 $ 97,620 $ 97,642 $ 92,450 $ 102,751 50,001 100K $ 1,968,033 $ 1,968,986 $ 1,669,448 $ 2,262,295 $ 49,462 $ 49,464 $ 47,023 $ 51,930 100,001 1M $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 > 1 Million $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 Large $ 4,912,447 $ 4,913,926 $ 4,192,562 $ 5,623,413 $ 147,082 $ 147,114 $ 139,489 $ 154,634 TNCWS Total $ 15,839,033 $ 15,843,493 $ 13,944,589 $ 17,746,446 $ 1,348,548 $ 1,347,867 $ 1,275,548 $ 1,421,750 All Types < 100 $ 5,931,826 $ 5,932,197 $ 5,335,905 $ 6,526,873 $ 818,770 $ 818,822 $ 785,579 $ 852,240 101 500 $ 7,697,281 $ 7,698,509 $ 7,052,797 $ 8,343,287 $ 985,474 $ 985,344 $ 948,744 $ 1,022,428 501 1,000 $ 7,850,115 $ 7,850,977 $ 7,140,347 $ 8,550,492 $ 894,121 $ 893,979 $ 857,713 $ 930,112 1,001 3,300 $ 28,096,082 $ 28,107,302 $ 25,013,237 $ 31,112,941 $ 2,513,076 $ 2,513,259 $ 2,385,844 $ 2,638,860 3,301 10K $ 82,441,074 $ 82,480,274 $ 72,001,197 $ 92,736,453 $ 4,778,740 $ 4,780,378 $ 4,490,053 $ 5,061,395 Small $ 132,016,378 $ 132,076,012 $ 117,133,837 $ 146,612,669 $ 9,990,180 $ 9,992,413 $ 9,500,535 $ 10,469,937 10,001 50K $ 370,043,201 $ 369,403,709 $ 318,986,312 $ 422,662,599 $ 12,110,501 $ 12,116,246 $ 11,474,165 $ 12,735,845 50,001 100K $ 203,412,954 $ 203,000,499 $ 174,414,725 $ 233,238,705 $ 5,761,889 $ 5,763,961 $ 5,471,965 $ 6,048,603 100,001 1M $ 605,388,458 $ 604,091,011 $ 517,074,776 $ 696,371,876 $ 14,897,387 $ 14,902,558 $ 14,199,143 $ 15,591,583 > 1 Million $ 418,660,846 $ 417,861,281 $ 351,835,994 $ 487,351,873 $ 10,534,917 $ 10,539,580 $ 9,944,657 $ 11,124,271 Large $ 1,597,505,458 $ 1,594,323,372 $ 1,362,384,082 $ 1,840,016,762 $ 43,304,695 $ 43,313,398 $ 41,111,043 $ 45,481,342 All Sizes $ 1,729,521,836 $ 1,726,678,008 $ 1,483,810,104 $ 1,981,791,620 $ 53,294,875 $ 53,308,745 $ 50,793,590 $ 55,773,535 Notes: All values in year 2000 dollars.

Detail may not add exactly to totals due to independent rounding.

Derived from LT2ESWTR Cost Model. Median Value Mean Value Median Value Mean Value Economic Analysis for the LT2ESWTR Proposal Q 21 June 2003 Exhibit Q. 20 Treatment Capital and O& M Costs by System Size for Alternative 3  High UV90 10B A3 High UV90 10B Capital Costs O& M Costs 90 Percent Confidence Bound 90 Percent Confidence Bound System Classification System Size ( population served) Lower ( 5th % tile) Upper ( 95th % tile) Lower ( 5th % tile) Upper ( 95th % tile)

CWSs < 100 $ 1,285,231 $ 1,284,887 $ 1,101,930 $ 1,468,690 $ 187,371 $ 187,429 $ 176,568 $ 198,117 101 500 $ 3,925,703 $ 3,923,926 $ 3,402,274 $ 4,451,429 $ 519,147 $ 519,387 $ 488,655 $ 549,257 501 1,000 $ 5,910,052 $ 5,905,488 $ 5,224,837 $ 6,597,321 $ 624,864 $ 624,818 $ 589,863 $ 659,492 1,001 3,300 $ 25,627,018 $ 25,618,816 $ 22,593,254 $ 28,699,632 $ 2,207,165 $ 2,207,173 $ 2,080,660 $ 2,333,091 3,301 10K $ 82,101,615 $ 82,050,485 $ 71,779,427 $ 92,414,427 $ 4,642,122 $ 4,641,390 $ 4,354,706 $ 4,926,955 Small $ 118,849,620 $ 118,782,105 $ 104,187,827 $ 133,534,603 $ 8,180,670 $ 8,180,159 $ 7,698,379 $ 8,659,985 10,001 50K $ 394,085,013 $ 394,114,582 $ 340,822,947 $ 447,105,356 $ 13,043,995 $ 13,045,575 $ 12,341,284 $ 13,747,332 50,001 100K $ 220,214,457 $ 220,205,103 $ 189,861,417 $ 250,393,797 $ 6,499,023 $ 6,501,679 $ 6,153,125 $ 6,849,899 100,001 1M $ 674,796,532 $ 674,855,914 $ 580,831,611 $ 767,939,201 $ 17,956,440 $ 17,960,801 $ 16,955,065 $ 18,955,370 > 1 Million $ 456,778,909 $ 456,844,619 $ 386,997,992 $ 526,172,455 $ 12,337,323 $ 12,338,510 $ 11,558,338 $ 13,111,748 Large $ 1,745,874,911 $ 1,745,584,051 $ 1,498,800,700 $ 1,991,264,106 $ 49,836,781 $ 49,848,140 $ 47,066,792 $ 52,627,298 CWS Total $ 1,864,724,531 $ 1,864,913,562 $ 1,606,103,073 $ 2,121,206,347 $ 58,017,451 $ 58,026,429 $ 54,985,336 $ 61,057,821 NTNCWSs < 100 $ 770,261 $ 768,903 $ 658,404 $ 880,858 $ 105,976 $ 105,958 $ 99,866 $ 112,072 101 500 $ 1,413,973 $ 1,411,857 $ 1,226,553 $ 1,599,176 $ 169,330 $ 169,317 $ 159,679 $ 178,918 501 1,000 $ 1,273,905 $ 1,272,700 $ 1,128,540 $ 1,418,961 $ 126,286 $ 126,304 $ 119,471 $ 133,209 1,001 3,300 $ 2,023,732 $ 2,022,821 $ 1,751,029 $ 2,295,193 $ 125,824 $ 125,801 $ 118,812 $ 132,903 3,301 10K $ 1,409,164 $ 1,407,668 $ 1,235,776 $ 1,580,107 $ 81,127 $ 81,124 $ 76,119 $ 86,064 Small $ 6,891,036 $ 6,885,449 $ 6,037,010 $ 7,726,094 $ 608,542 $ 608,429 $ 574,604 $ 642,726 10,001 50K $ 3,206,866 $ 3,210,329 $ 2,758,917 $ 3,646,980 $ 95,357 $ 95,372 $ 90,197 $ 100,557 50,001 100K $ 1,017,650 $ 1,018,751 $ 873,632 $ 1,159,865 $ 25,895 $ 25,894 $ 24,431 $ 27,377 100,001 1M $ 1,611,978 $ 1,613,858 $ 1,388,611 $ 1,833,039 $ 42,928 $ 42,933 $ 40,562 $ 45,307 > 1 Million $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 Large $ 5,836,493 $ 5,842,667 $ 5,021,698 $ 6,640,923 $ 164,179 $ 164,159 $ 155,318 $ 173,129 NTNCWS Total $ 12,727,529 $ 12,729,130 $ 11,205,492 $ 14,244,008 $ 772,722 $ 772,598 $ 733,025 $ 812,621 TNCWSs < 100 $ 3,868,979 $ 3,871,429 $ 3,308,780 $ 4,427,748 $ 525,769 $ 525,589 $ 495,561 $ 555,977 101 500 $ 2,356,549 $ 2,357,424 $ 2,038,063 $ 2,674,420 $ 296,818 $ 296,677 $ 279,870 $ 313,776 501 1,000 $ 1,050,878 $ 1,050,578 $ 931,910 $ 1,171,671 $ 107,918 $ 107,887 $ 102,064 $ 113,827 1,001 3,300 $ 1,787,741 $ 1,787,602 $ 1,570,355 $ 2,006,520 $ 147,731 $ 147,686 $ 139,436 $ 156,016 3,301 10K $ 2,163,913 $ 2,163,554 $ 1,900,406 $ 2,431,094 $ 121,039 $ 121,034 $ 113,600 $ 128,373 Small $ 11,228,059 $ 11,229,650 $ 9,792,112 $ 12,659,938 $ 1,199,275 $ 1,198,639 $ 1,131,358 $ 1,266,729 10,001 50K $ 3,191,166 $ 3,190,103 $ 2,758,137 $ 3,621,244 $ 107,235 $ 107,269 $ 101,539 $ 113,015 50,001 100K $ 2,188,153 $ 2,186,844 $ 1,880,226 $ 2,494,144 $ 58,904 $ 58,915 $ 55,676 $ 62,138 100,001 1M $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 > 1 Million $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 Large $ 5,379,319 $ 5,376,835 $ 4,639,137 $ 6,115,887 $ 166,139 $ 166,195 $ 157,366 $ 175,075 TNCWS Total $ 16,607,378 $ 16,607,444 $ 14,736,882 $ 18,506,557 $ 1,365,413 $ 1,364,743 $ 1,291,899 $ 1,439,020 All Types < 100 $ 5,924,471 $ 5,926,191 $ 5,328,212 $ 6,515,846 $ 819,116 $ 819,025 $ 786,241 $ 851,961 101 500 $ 7,696,225 $ 7,692,621 $ 7,058,462 $ 8,332,100 $ 985,295 $ 985,480 $ 948,945 $ 1,021,430 501 1,000 $ 8,234,835 $ 8,229,229 $ 7,522,732 $ 8,949,137 $ 859,068 $ 859,153 $ 822,823 $ 895,000 1,001 3,300 $ 29,438,491 $ 29,427,776 $ 26,368,445 $ 32,502,245 $ 2,480,721 $ 2,480,956 $ 2,353,612 $ 2,607,010 3,301 10K $ 85,674,693 $ 85,626,331 $ 75,361,273 $ 96,015,776 $ 4,844,288 $ 4,843,118 $ 4,556,545 $ 5,129,571 Small $ 136,968,714 $ 136,877,739 $ 122,238,629 $ 151,731,849 $ 9,988,487 $ 9,988,169 $ 9,500,524 $ 10,472,110 10,001 50K $ 400,483,045 $ 400,528,604 $ 347,202,580 $ 453,520,944 $ 13,246,586 $ 13,248,974 $ 12,543,179 $ 13,951,589 50,001 100K $ 223,420,259 $ 223,449,377 $ 193,050,551 $ 253,637,675 $ 6,583,822 $ 6,586,533 $ 6,238,371 $ 6,933,941 100,001 1M $ 676,408,510 $ 676,507,007 $ 582,432,028 $ 769,665,114 $ 17,999,368 $ 18,004,013 $ 16,997,102 $ 18,997,992 > 1 Million $ 456,778,909 $ 456,844,619 $ 386,997,992 $ 526,172,455 $ 12,337,323 $ 12,338,510 $ 11,558,338 $ 13,111,748 Large $ 1,757,090,724 $ 1,757,259,447 $ 1,509,872,386 $ 2,002,792,681 $ 50,167,099 $ 50,178,394 $ 47,400,945 $ 52,955,620 All Sizes $ 1,894,059,438 $ 1,893,981,470 $ 1,635,034,739 $ 2,150,927,239 $ 60,155,586 $ 60,165,531 $ 57,132,027 $ 63,200,529 Notes: All values in year 2000 dollars.

Detail may not add exactly to totals due to independent rounding.

Derived from LT2ESWTR Cost Model. Median Value Mean Value Median Value Mean Value Economic Analysis for the LT2ESWTR Proposal Q 22 June 2003 Exhibit Q. 21 Treatment Capital and O& M Costs by System Size for Alternative 3  Low UV90 10 A3 Low UV90 10 Capital Costs O& M Costs 90 Percent Confidence Bound 90 Percent Confidence Bound System Classification System Size ( population served) Lower ( 5th % tile) Upper ( 95th % tile) Lower ( 5th % tile) Upper ( 95th % tile)

CWSs < 100 $ 445,102 $ 445,218 $ 367,608 $ 522,483 $ 56,979 $ 56,949 $ 53,125 $ 60,841 101 500 $ 1,337,983 $ 1,338,062 $ 1,113,520 $ 1,563,206 $ 165,170 $ 165,104 $ 153,388 $ 176,936 501 1,000 $ 1,989,268 $ 1,990,272 $ 1,711,208 $ 2,267,527 $ 212,744 $ 212,690 $ 199,573 $ 225,930 1,001 3,300 $ 8,383,990 $ 8,386,562 $ 7,180,668 $ 9,587,861 $ 718,209 $ 717,747 $ 668,871 $ 767,942 3,301 10K $ 28,094,599 $ 28,106,669 $ 23,902,320 $ 32,294,134 $ 1,659,349 $ 1,658,121 $ 1,530,154 $ 1,790,634 Small $ 40,250,943 $ 40,267,038 $ 34,290,618 $ 46,228,691 $ 2,812,451 $ 2,810,590 $ 2,606,831 $ 3,019,529 10,001 50K $ 130,239,277 $ 130,168,001 $ 111,136,880 $ 149,401,362 $ 4,214,895 $ 4,214,552 $ 3,971,310 $ 4,460,740 50,001 100K $ 70,546,145 $ 70,508,518 $ 59,871,462 $ 81,255,689 $ 1,931,779 $ 1,931,847 $ 1,824,487 $ 2,040,030 100,001 1M $ 214,054,067 $ 213,936,974 $ 180,961,858 $ 247,052,953 $ 4,951,663 $ 4,951,306 $ 4,697,695 $ 5,207,220 > 1 Million $ 225,431,893 $ 225,417,065 $ 187,134,780 $ 263,745,670 $ 5,561,959 $ 5,561,963 $ 5,197,741 $ 5,927,130 Large $ 640,271,382 $ 639,999,760 $ 539,116,874 $ 741,498,221 $ 16,660,297 $ 16,661,422 $ 15,696,591 $ 17,625,956 CWS Total $ 680,522,325 $ 680,519,811 $ 576,377,521 $ 785,212,660 $ 19,472,748 $ 19,470,687 $ 18,410,913 $ 20,545,914 NTNCWSs < 100 $ 261,839 $ 261,811 $ 215,996 $ 308,366 $ 30,327 $ 30,334 $ 28,309 $ 32,284 101 500 $ 446,324 $ 446,220 $ 374,294 $ 519,582 $ 46,574 $ 46,585 $ 43,354 $ 49,695 501 1,000 $ 332,680 $ 332,718 $ 286,357 $ 379,421 $ 30,516 $ 30,527 $ 28,758 $ 32,243 1,001 3,300 $ 441,231 $ 441,138 $ 379,573 $ 504,026 $ 32,607 $ 32,611 $ 30,425 $ 34,754 3,301 10K $ 373,693 $ 373,669 $ 317,775 $ 430,196 $ 23,963 $ 23,959 $ 21,999 $ 25,902 Small $ 1,855,768 $ 1,855,567 $ 1,576,546 $ 2,139,653 $ 163,986 $ 163,997 $ 153,052 $ 174,692 10,001 50K $ 958,437 $ 958,567 $ 814,424 $ 1,101,095 $ 26,947 $ 26,949 $ 25,478 $ 28,442 50,001 100K $ 292,193 $ 292,300 $ 246,589 $ 337,605 $ 6,304 $ 6,305 $ 5,974 $ 6,640 100,001 1M $ 455,606 $ 455,654 $ 386,012 $ 524,648 $ 10,355 $ 10,357 $ 9,866 $ 10,850 > 1 Million $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 Large $ 1,706,236 $ 1,706,648 $ 1,447,485 $ 1,963,061 $ 43,606 $ 43,620 $ 41,330 $ 45,935 NTNCWS Total $ 3,562,003 $ 3,558,497 $ 3,128,904 $ 4,000,398 $ 207,592 $ 207,706 $ 195,612 $ 219,391 TNCWSs < 100 $ 1,324,856 $ 1,324,175 $ 1,092,429 $ 1,558,716 $ 149,888 $ 149,889 $ 140,273 $ 159,450 101 500 $ 763,344 $ 763,005 $ 636,004 $ 891,247 $ 82,010 $ 82,001 $ 76,559 $ 87,434 501 1,000 $ 279,636 $ 279,692 $ 240,544 $ 319,361 $ 26,298 $ 26,301 $ 24,765 $ 27,820 1,001 3,300 $ 454,345 $ 454,388 $ 384,193 $ 524,946 $ 39,352 $ 39,344 $ 36,590 $ 42,116 3,301 10K $ 575,996 $ 575,894 $ 490,281 $ 663,138 $ 35,942 $ 35,945 $ 33,019 $ 38,876 Small $ 3,398,178 $ 3,397,078 $ 2,841,931 $ 3,955,626 $ 333,491 $ 333,429 $ 311,636 $ 355,239 10,001 50K $ 957,629 $ 956,700 $ 818,053 $ 1,097,025 $ 31,421 $ 31,425 $ 29,670 $ 33,141 50,001 100K $ 634,741 $ 634,418 $ 536,246 $ 732,819 $ 14,899 $ 14,900 $ 14,109 $ 15,678 100,001 1M $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 > 1 Million $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 Large $ 1,592,370 $ 1,590,965 $ 1,354,409 $ 1,829,072 $ 46,320 $ 46,326 $ 43,785 $ 48,832 TNCWS Total $ 4,990,548 $ 4,986,232 $ 4,349,471 $ 5,637,583 $ 379,811 $ 379,791 $ 356,676 $ 402,659 All Types < 100 $ 2,031,798 $ 2,032,457 $ 1,782,626 $ 2,283,937 $ 237,194 $ 237,174 $ 226,401 $ 248,046 101 500 $ 2,547,652 $ 2,547,344 $ 2,280,086 $ 2,818,165 $ 293,755 $ 293,768 $ 280,030 $ 307,525 501 1,000 $ 2,601,584 $ 2,600,660 $ 2,315,550 $ 2,889,255 $ 269,558 $ 269,502 $ 256,155 $ 283,128 1,001 3,300 $ 9,279,566 $ 9,281,027 $ 8,075,801 $ 10,488,843 $ 790,167 $ 789,578 $ 740,776 $ 840,054 3,301 10K $ 29,044,288 $ 29,058,850 $ 24,858,621 $ 33,236,289 $ 1,719,254 $ 1,717,813 $ 1,589,941 $ 1,850,445 Small $ 45,504,888 $ 45,500,260 $ 39,543,523 $ 51,497,160 $ 3,309,928 $ 3,307,733 $ 3,103,196 $ 3,518,862 10,001 50K $ 132,155,343 $ 132,094,550 $ 113,065,457 $ 151,317,422 $ 4,273,264 $ 4,272,794 $ 4,030,071 $ 4,519,466 50,001 100K $ 71,473,079 $ 71,450,644 $ 60,784,189 $ 82,178,003 $ 1,952,982 $ 1,953,005 $ 1,845,644 $ 2,061,272 100,001 1M $ 214,509,673 $ 214,374,723 $ 181,412,106 $ 247,538,298 $ 4,962,018 $ 4,961,669 $ 4,708,126 $ 5,217,417 > 1 Million $ 225,431,893 $ 225,417,065 $ 187,134,780 $ 263,745,670 $ 5,561,959 $ 5,561,963 $ 5,197,741 $ 5,927,130 Large $ 643,569,988 $ 643,378,184 $ 542,421,029 $ 744,869,583 $ 16,750,223 $ 16,751,352 $ 15,785,186 $ 17,716,276 All Sizes $ 689,074,876 $ 689,075,405 $ 584,898,755 $ 793,750,856 $ 20,060,151 $ 20,058,509 $ 18,998,618 $ 21,133,073 Notes: All values in year 2000 dollars.

Detail may not add exactly to totals due to independent rounding.

Derived from LT2ESWTR Cost Model. Median Value Mean Value Median Value Mean Value Economic Analysis for the LT2ESWTR Proposal Q 23 June 2003 Exhibit Q. 22 Treatment Capital and O& M Costs by System Size for Alternative 3  Low UV90 10B A3 Low UV90 10B Capital Costs O& M Costs 90 Percent Confidence Bound 90 Percent Confidence Bound System Classification System Size ( population served) Lower ( 5th % tile) Upper ( 95th % tile) Lower ( 5th % tile) Upper ( 95th % tile)

CWSs < 100 $ 444,849 $ 444,915 $ 366,560 $ 523,194 $ 56,970 $ 56,969 $ 53,143 $ 60,819 101 500 $ 1,337,464 $ 1,337,837 $ 1,110,658 $ 1,564,891 $ 165,140 $ 165,127 $ 153,459 $ 176,878 501 1,000 $ 2,029,535 $ 2,029,495 $ 1,744,727 $ 2,313,884 $ 211,973 $ 212,008 $ 199,086 $ 224,831 1,001 3,300 $ 8,533,874 $ 8,533,041 $ 7,303,641 $ 9,758,129 $ 720,783 $ 720,698 $ 672,475 $ 769,292 3,301 10K $ 28,490,304 $ 28,484,083 $ 24,228,347 $ 32,753,982 $ 1,676,979 $ 1,676,193 $ 1,549,541 $ 1,805,394 Small $ 40,836,027 $ 40,832,928 $ 34,773,671 $ 46,897,190 $ 2,831,845 $ 2,831,137 $ 2,629,593 $ 3,035,128 10,001 50K $ 135,188,345 $ 135,280,743 $ 115,474,182 $ 154,711,522 $ 4,445,669 $ 4,445,734 $ 4,201,760 $ 4,688,635 50,001 100K $ 73,834,218 $ 73,890,450 $ 62,830,806 $ 84,791,731 $ 2,096,694 $ 2,096,672 $ 1,986,101 $ 2,207,434 100,001 1M $ 225,238,553 $ 225,389,828 $ 191,239,977 $ 259,143,058 $ 5,530,666 $ 5,531,181 $ 5,250,935 $ 5,810,510 > 1 Million $ 231,394,425 $ 231,539,122 $ 192,040,597 $ 270,276,857 $ 5,887,522 $ 5,888,960 $ 5,509,629 $ 6,264,592 Large $ 665,655,541 $ 666,041,712 $ 561,648,238 $ 768,977,585 $ 17,960,551 $ 17,964,163 $ 16,959,494 $ 18,962,131 CWS Total $ 706,491,568 $ 706,691,321 $ 599,424,667 $ 813,246,786 $ 20,792,396 $ 20,795,785 $ 19,696,581 $ 21,886,920 NTNCWSs < 100 $ 262,034 $ 262,235 $ 216,308 $ 307,303 $ 30,342 $ 30,332 $ 28,360 $ 32,293 101 500 $ 446,587 $ 447,263 $ 374,351 $ 518,475 $ 46,599 $ 46,589 $ 43,450 $ 49,692 501 1,000 $ 342,119 $ 342,501 $ 296,630 $ 388,440 $ 30,340 $ 30,333 $ 28,628 $ 32,032 1,001 3,300 $ 460,815 $ 461,150 $ 399,052 $ 522,839 $ 32,707 $ 32,714 $ 30,579 $ 34,821 3,301 10K $ 381,973 $ 382,384 $ 326,546 $ 437,441 $ 24,331 $ 24,337 $ 22,410 $ 26,230 Small $ 1,893,528 $ 1,895,745 $ 1,614,995 $ 2,171,542 $ 164,318 $ 164,300 $ 153,643 $ 174,808 10,001 50K $ 998,850 $ 999,331 $ 854,549 $ 1,141,895 $ 28,920 $ 28,931 $ 27,397 $ 30,452 50,001 100K $ 309,449 $ 309,710 $ 263,773 $ 355,067 $ 7,156 $ 7,158 $ 6,791 $ 7,525 100,001 1M $ 482,407 $ 482,607 $ 412,873 $ 551,968 $ 11,746 $ 11,747 $ 11,190 $ 12,307 > 1 Million $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 Large $ 1,790,706 $ 1,791,751 $ 1,531,272 $ 2,049,445 $ 47,822 $ 47,838 $ 45,404 $ 50,283 NTNCWS Total $ 3,684,234 $ 3,686,162 $ 3,253,719 $ 4,117,435 $ 212,140 $ 212,133 $ 200,393 $ 223,842 TNCWSs < 100 $ 1,323,249 $ 1,323,690 $ 1,086,972 $ 1,554,543 $ 149,875 $ 149,910 $ 140,124 $ 159,335 101 500 $ 762,336 $ 762,658 $ 632,969 $ 888,970 $ 82,002 $ 82,027 $ 76,478 $ 87,362 501 1,000 $ 287,343 $ 287,174 $ 247,448 $ 326,312 $ 26,148 $ 26,162 $ 24,619 $ 27,623 1,001 3,300 $ 476,563 $ 476,422 $ 405,738 $ 546,102 $ 39,662 $ 39,672 $ 36,888 $ 42,387 3,301 10K $ 587,734 $ 587,560 $ 500,342 $ 673,223 $ 36,460 $ 36,478 $ 33,530 $ 39,360 Small $ 3,437,225 $ 3,438,140 $ 2,872,877 $ 3,988,378 $ 334,146 $ 334,271 $ 312,108 $ 355,686 10,001 50K $ 995,449 $ 995,182 $ 853,984 $ 1,136,342 $ 33,310 $ 33,310 $ 31,556 $ 35,082 50,001 100K $ 669,260 $ 669,129 $ 569,593 $ 768,497 $ 16,696 $ 16,696 $ 15,847 $ 17,539 100,001 1M $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 > 1 Million $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 Large $ 1,664,709 $ 1,664,352 $ 1,423,668 $ 1,904,925 $ 50,006 $ 50,004 $ 47,420 $ 52,598 TNCWS Total $ 5,101,935 $ 5,104,356 $ 4,459,905 $ 5,745,658 $ 384,152 $ 384,265 $ 360,833 $ 406,697 All Types < 100 $ 2,030,132 $ 2,029,868 $ 1,781,305 $ 2,274,543 $ 237,186 $ 237,289 $ 226,297 $ 247,735 101 500 $ 2,546,387 $ 2,547,647 $ 2,276,674 $ 2,815,340 $ 293,741 $ 293,756 $ 280,200 $ 307,148 501 1,000 $ 2,658,997 $ 2,659,031 $ 2,366,778 $ 2,949,997 $ 268,460 $ 268,500 $ 255,297 $ 281,538 1,001 3,300 $ 9,471,253 $ 9,471,450 $ 8,242,530 $ 10,708,112 $ 793,152 $ 793,121 $ 744,526 $ 841,916 3,301 10K $ 29,460,011 $ 29,455,693 $ 25,184,208 $ 33,735,598 $ 1,737,770 $ 1,737,286 $ 1,610,566 $ 1,865,938 Small $ 46,166,780 $ 46,149,523 $ 40,098,802 $ 52,293,552 $ 3,330,309 $ 3,330,482 $ 3,126,151 $ 3,534,994 10,001 50K $ 137,182,643 $ 137,281,497 $ 117,467,949 $ 156,738,312 $ 4,507,899 $ 4,508,276 $ 4,264,073 $ 4,750,139 50,001 100K $ 74,812,927 $ 74,872,379 $ 63,803,088 $ 85,734,955 $ 2,120,546 $ 2,120,469 $ 2,009,818 $ 2,230,978 100,001 1M $ 225,720,961 $ 225,865,951 $ 191,720,280 $ 259,605,334 $ 5,542,411 $ 5,542,885 $ 5,262,607 $ 5,822,204 > 1 Million $ 231,394,425 $ 231,539,122 $ 192,040,597 $ 270,276,857 $ 5,887,522 $ 5,888,960 $ 5,509,629 $ 6,264,592 Large $ 669,110,956 $ 669,510,847 $ 565,167,052 $ 772,397,569 $ 18,058,379 $ 18,062,008 $ 17,057,332 $ 19,059,979 All Sizes $ 715,277,737 $ 715,531,919 $ 608,234,914 $ 822,152,232 $ 21,388,688 $ 21,393,472 $ 20,291,253 $ 22,483,487 Notes: All values in year 2000 dollars.

Detail may not add exactly to totals due to independent rounding.

Derived from LT2ESWTR Cost Model. Median Value Mean Value Median Value Mean Value Economic Analysis for the LT2ESWTR Proposal Q 24 June 2003 Exhibit Q. 23 Treatment Capital and O& M Costs by System Size For Alternative 4  ICR UV90 10 A4 ICR UV90 10 Capital Costs O& M Costs 90 Percent Confidence Bound 90 Percent Confidence Bound System Classification System Size ( population served) Lower ( 5th % tile) Upper ( 95th % tile) Lower ( 5th % tile) Upper ( 95th % tile)

CWSs < 100 $ 717,443 $ 716,787 $ 591,719 $ 844,439 $ 89,996 $ 90,023 $ 83,968 $ 95,992 101 500 $ 2,094,421 $ 2,093,672 $ 1,738,201 $ 2,449,253 $ 249,292 $ 249,357 $ 231,877 $ 266,603 501 1,000 $ 2,809,893 $ 2,808,409 $ 2,397,577 $ 3,221,231 $ 288,191 $ 288,247 $ 270,317 $ 305,816 1,001 3,300 $ 12,074,688 $ 12,069,679 $ 10,257,044 $ 13,884,344 $ 1,029,433 $ 1,029,492 $ 956,914 $ 1,100,649 3,301 10K $ 39,273,371 $ 39,256,493 $ 33,217,634 $ 45,281,587 $ 2,415,894 $ 2,416,375 $ 2,220,040 $ 2,611,037 Small $ 56,969,816 $ 56,932,457 $ 48,247,749 $ 65,638,159 $ 4,072,806 $ 4,073,685 $ 3,765,139 $ 4,376,485 10,001 50K $ 135,759,270 $ 135,556,540 $ 117,016,702 $ 154,949,086 $ 5,902,999 $ 5,904,182 $ 5,650,299 $ 6,153,438 50,001 100K $ 73,345,902 $ 73,237,849 $ 62,897,848 $ 84,077,528 $ 2,969,836 $ 2,970,423 $ 2,857,771 $ 3,080,546 100,001 1M $ 221,764,695 $ 221,450,446 $ 189,226,608 $ 255,324,263 $ 6,539,300 $ 6,540,789 $ 6,276,046 $ 6,800,800 > 1 Million $ 228,281,560 $ 227,952,417 $ 190,466,614 $ 267,207,219 $ 5,963,515 $ 5,965,809 $ 5,602,908 $ 6,326,000 Large $ 659,151,427 $ 658,199,969 $ 559,844,033 $ 761,469,627 $ 21,375,650 $ 21,380,918 $ 20,388,794 $ 22,351,483 CWS Total $ 716,121,243 $ 715,248,055 $ 612,736,209 $ 822,523,560 $ 25,448,456 $ 25,452,265 $ 24,326,520 $ 26,561,283 NTNCWSs < 100 $ 427,397 $ 427,586 $ 351,244 $ 503,455 $ 49,319 $ 49,313 $ 46,118 $ 52,510 101 500 $ 727,013 $ 727,526 $ 607,631 $ 847,858 $ 75,466 $ 75,447 $ 70,365 $ 80,545 501 1,000 $ 525,496 $ 525,772 $ 449,214 $ 602,087 $ 47,600 $ 47,600 $ 44,813 $ 50,366 1,001 3,300 $ 724,782 $ 724,699 $ 622,993 $ 827,319 $ 51,544 $ 51,550 $ 48,045 $ 55,050 3,301 10K $ 595,637 $ 596,024 $ 503,200 $ 688,411 $ 38,541 $ 38,543 $ 35,377 $ 41,720 Small $ 3,000,324 $ 3,003,330 $ 2,538,513 $ 3,465,591 $ 262,469 $ 262,407 $ 244,988 $ 279,875 10,001 50K $ 994,479 $ 996,820 $ 851,915 $ 1,133,528 $ 38,413 $ 38,406 $ 36,845 $ 39,980 50,001 100K $ 298,524 $ 299,202 $ 253,066 $ 342,658 $ 8,882 $ 8,880 $ 8,527 $ 9,235 100,001 1M $ 475,362 $ 476,413 $ 405,274 $ 543,526 $ 14,265 $ 14,261 $ 13,743 $ 14,783 > 1 Million $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 Large $ 1,768,366 $ 1,772,057 $ 1,510,861 $ 2,019,865 $ 61,560 $ 61,540 $ 59,121 $ 64,002 NTNCWS Total $ 4,768,690 $ 4,766,855 $ 4,185,697 $ 5,364,022 $ 324,029 $ 323,972 $ 305,547 $ 342,292 TNCWSs < 100 $ 2,158,649 $ 2,158,416 $ 1,775,302 $ 2,543,575 $ 244,025 $ 244,023 $ 228,096 $ 259,963 101 500 $ 1,241,677 $ 1,242,086 $ 1,031,744 $ 1,451,627 $ 133,100 $ 133,099 $ 124,091 $ 142,183 501 1,000 $ 441,733 $ 441,648 $ 377,267 $ 506,155 $ 41,108 $ 41,107 $ 38,662 $ 43,550 1,001 3,300 $ 754,001 $ 754,354 $ 638,679 $ 869,152 $ 62,538 $ 62,512 $ 58,107 $ 67,044 3,301 10K $ 917,567 $ 917,907 $ 775,734 $ 1,059,098 $ 57,885 $ 57,855 $ 53,163 $ 62,663 Small $ 5,513,626 $ 5,513,726 $ 4,601,093 $ 6,425,585 $ 538,656 $ 538,567 $ 502,662 $ 574,695 10,001 50K $ 1,005,949 $ 1,006,452 $ 866,364 $ 1,144,729 $ 45,792 $ 45,796 $ 43,962 $ 47,618 50,001 100K $ 655,348 $ 655,739 $ 557,663 $ 752,777 $ 22,437 $ 22,438 $ 21,604 $ 23,264 100,001 1M $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 > 1 Million $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 Large $ 1,661,297 $ 1,662,307 $ 1,424,402 $ 1,895,989 $ 68,229 $ 68,235 $ 65,579 $ 70,882 TNCWS Total $ 7,174,923 $ 7,178,964 $ 6,200,040 $ 8,172,543 $ 606,885 $ 606,791 $ 569,854 $ 644,028 All Types < 100 $ 3,303,488 $ 3,301,121 $ 2,894,381 $ 3,710,150 $ 383,340 $ 383,419 $ 365,968 $ 400,920 101 500 $ 4,063,111 $ 4,061,529 $ 3,632,879 $ 4,493,959 $ 457,857 $ 457,778 $ 437,050 $ 478,552 501 1,000 $ 3,777,121 $ 3,774,147 $ 3,352,659 $ 4,200,123 $ 376,900 $ 376,968 $ 358,449 $ 395,056 1,001 3,300 $ 13,553,471 $ 13,550,610 $ 11,740,536 $ 15,377,779 $ 1,143,515 $ 1,143,803 $ 1,070,799 $ 1,215,359 3,301 10K $ 40,786,575 $ 40,770,959 $ 34,758,896 $ 46,814,886 $ 2,512,320 $ 2,512,864 $ 2,316,940 $ 2,707,382 Small $ 65,483,766 $ 65,459,458 $ 56,748,873 $ 74,247,466 $ 4,873,931 $ 4,874,698 $ 4,564,391 $ 5,178,941 10,001 50K $ 137,759,698 $ 137,565,135 $ 119,046,403 $ 156,983,219 $ 5,987,204 $ 5,988,092 $ 5,734,116 $ 6,237,741 50,001 100K $ 74,299,774 $ 74,184,085 $ 63,862,249 $ 85,025,431 $ 3,001,155 $ 3,001,806 $ 2,889,225 $ 3,112,029 100,001 1M $ 222,240,058 $ 221,929,125 $ 189,714,341 $ 255,805,535 $ 6,553,564 $ 6,555,160 $ 6,290,383 $ 6,814,888 > 1 Million $ 228,281,560 $ 227,952,417 $ 190,466,614 $ 267,207,219 $ 5,963,515 $ 5,965,809 $ 5,602,908 $ 6,326,000 Large $ 662,581,090 $ 661,605,703 $ 563,281,347 $ 764,952,520 $ 21,505,439 $ 21,510,735 $ 20,518,316 $ 22,480,497 All Sizes $ 728,064,856 $ 727,119,307 $ 624,621,556 $ 834,466,328 $ 26,379,370 $ 26,382,620 $ 25,251,936 $ 27,490,349 Notes: All values in year 2000 dollars.

Detail may not add exactly to totals due to independent rounding.

Derived from LT2ESWTR Cost Model. Median Value Mean Value Median Value Mean Value Economic Analysis for the LT2ESWTR Proposal Q 25 June 2003 Exhibit Q. 24 Treatment Capital and O& M Costs by System Size For Alternative 4  ICR UV90 10B A4 ICR UV90 10B Capital Costs O& M Costs 90 Percent Confidence Bound 90 Percent Confidence Bound System Classification System Size ( population served) Lower ( 5th % tile) Upper ( 95th % tile) Lower ( 5th % tile) Upper ( 95th % tile)

CWSs < 100 $ 717,443 $ 716,787 $ 591,719 $ 844,439 $ 89,996 $ 90,023 $ 83,968 $ 95,992 101 500 $ 2,094,421 $ 2,093,672 $ 1,738,201 $ 2,449,253 $ 249,292 $ 249,357 $ 231,877 $ 266,603 501 1,000 $ 2,818,306 $ 2,817,133 $ 2,406,183 $ 3,231,266 $ 286,983 $ 287,043 $ 269,075 $ 304,570 1,001 3,300 $ 12,107,356 $ 12,100,200 $ 10,292,244 $ 13,917,539 $ 1,028,396 $ 1,028,507 $ 955,712 $ 1,099,672 3,301 10K $ 39,382,196 $ 39,356,559 $ 33,327,992 $ 45,387,183 $ 2,421,516 $ 2,422,180 $ 2,225,660 $ 2,616,738 Small $ 57,119,722 $ 57,075,450 $ 48,356,725 $ 65,806,641 $ 4,076,183 $ 4,076,888 $ 3,768,110 $ 4,379,720 10,001 50K $ 138,904,499 $ 138,767,939 $ 120,023,549 $ 158,256,924 $ 6,053,381 $ 6,054,799 $ 5,796,205 $ 6,305,235 50,001 100K $ 75,420,455 $ 75,332,993 $ 64,894,964 $ 86,182,913 $ 3,077,074 $ 3,077,704 $ 2,962,530 $ 3,190,866 100,001 1M $ 228,830,458 $ 228,523,376 $ 195,914,395 $ 262,460,370 $ 6,918,370 $ 6,920,770 $ 6,641,180 $ 7,195,990 > 1 Million $ 232,010,120 $ 231,657,935 $ 194,113,425 $ 270,955,148 $ 6,177,900 $ 6,180,560 $ 5,807,210 $ 6,550,777 Large $ 675,165,533 $ 674,318,575 $ 575,159,253 $ 777,880,762 $ 22,226,725 $ 22,232,725 $ 21,215,980 $ 23,234,254 CWS Total $ 732,285,255 $ 731,329,854 $ 628,645,862 $ 838,617,655 $ 26,302,908 $ 26,307,940 $ 25,159,473 $ 27,438,471 NTNCWSs < 100 $ 426,681 $ 426,688 $ 350,713 $ 501,934 $ 49,326 $ 49,331 $ 46,087 $ 52,570 101 500 $ 725,836 $ 725,115 $ 606,913 $ 843,200 $ 75,477 $ 75,465 $ 70,334 $ 80,656 501 1,000 $ 526,652 $ 526,130 $ 450,858 $ 601,405 $ 47,308 $ 47,312 $ 44,516 $ 50,089 1,001 3,300 $ 731,213 $ 730,667 $ 630,712 $ 830,708 $ 51,435 $ 51,420 $ 47,969 $ 54,937 3,301 10K $ 597,010 $ 596,308 $ 504,844 $ 687,687 $ 38,655 $ 38,635 $ 35,527 $ 41,812 Small $ 3,007,392 $ 3,003,578 $ 2,546,813 $ 3,460,881 $ 262,201 $ 262,116 $ 244,726 $ 279,826 10,001 50K $ 1,020,348 $ 1,019,229 $ 878,974 $ 1,162,531 $ 39,713 $ 39,718 $ 38,120 $ 41,303 50,001 100K $ 309,487 $ 309,306 $ 264,557 $ 354,571 $ 9,442 $ 9,443 $ 9,070 $ 9,819 100,001 1M $ 492,432 $ 492,059 $ 422,932 $ 561,828 $ 15,180 $ 15,183 $ 14,626 $ 15,738 > 1 Million $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 Large $ 1,822,267 $ 1,820,745 $ 1,565,921 $ 2,078,281 $ 64,334 $ 64,342 $ 61,831 $ 66,844 NTNCWS Total $ 4,829,658 $ 4,824,839 $ 4,246,770 $ 5,416,841 $ 326,535 $ 326,524 $ 307,983 $ 344,995 TNCWSs < 100 $ 2,156,792 $ 2,157,857 $ 1,768,081 $ 2,536,515 $ 243,968 $ 244,036 $ 227,997 $ 259,459 101 500 $ 1,240,522 $ 1,241,022 $ 1,028,461 $ 1,448,328 $ 133,066 $ 133,113 $ 124,003 $ 141,824 501 1,000 $ 443,050 $ 442,933 $ 378,178 $ 506,650 $ 40,861 $ 40,881 $ 38,372 $ 43,271 1,001 3,300 $ 762,120 $ 761,617 $ 646,224 $ 875,991 $ 62,510 $ 62,526 $ 57,972 $ 66,980 3,301 10K $ 920,316 $ 919,842 $ 777,648 $ 1,059,898 $ 58,038 $ 58,073 $ 53,241 $ 62,810 Small $ 5,522,800 $ 5,523,269 $ 4,598,702 $ 6,430,320 $ 538,442 $ 538,733 $ 502,437 $ 573,797 10,001 50K $ 1,030,566 $ 1,030,557 $ 891,374 $ 1,170,110 $ 47,016 $ 47,012 $ 45,170 $ 48,885 50,001 100K $ 677,405 $ 677,251 $ 579,568 $ 775,380 $ 23,605 $ 23,609 $ 22,735 $ 24,472 100,001 1M $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 > 1 Million $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 Large $ 1,707,971 $ 1,707,643 $ 1,471,697 $ 1,944,578 $ 70,621 $ 70,622 $ 67,900 $ 73,340 TNCWS Total $ 7,230,772 $ 7,234,020 $ 6,246,724 $ 8,210,403 $ 609,063 $ 609,181 $ 571,663 $ 645,331 All Types < 100 $ 3,300,916 $ 3,301,396 $ 2,891,520 $ 3,705,143 $ 383,290 $ 383,443 $ 365,969 $ 400,384 101 500 $ 4,060,779 $ 4,063,856 $ 3,626,354 $ 4,483,103 $ 457,834 $ 457,814 $ 436,712 $ 478,709 501 1,000 $ 3,788,009 $ 3,789,187 $ 3,362,482 $ 4,213,694 $ 375,152 $ 375,181 $ 356,795 $ 393,151 1,001 3,300 $ 13,600,689 $ 13,595,465 $ 11,776,285 $ 15,423,661 $ 1,142,341 $ 1,142,579 $ 1,069,239 $ 1,214,165 3,301 10K $ 40,899,522 $ 40,866,280 $ 34,844,936 $ 46,913,365 $ 2,518,209 $ 2,518,496 $ 2,322,580 $ 2,713,254 Small $ 65,649,914 $ 65,621,437 $ 56,916,111 $ 74,461,342 $ 4,876,826 $ 4,877,389 $ 4,569,402 $ 5,184,283 10,001 50K $ 140,955,413 $ 140,824,145 $ 122,086,379 $ 160,292,553 $ 6,140,109 $ 6,141,529 $ 5,882,576 $ 6,392,268 50,001 100K $ 76,407,347 $ 76,309,652 $ 65,866,999 $ 87,165,776 $ 3,110,121 $ 3,110,745 $ 2,995,623 $ 3,223,717 100,001 1M $ 229,322,890 $ 229,024,158 $ 196,413,802 $ 262,954,707 $ 6,933,550 $ 6,935,812 $ 6,656,320 $ 7,211,350 > 1 Million $ 232,010,120 $ 231,657,935 $ 194,113,425 $ 270,955,148 $ 6,177,900 $ 6,180,560 $ 5,807,210 $ 6,550,777 Large $ 678,695,770 $ 677,879,572 $ 578,667,911 $ 781,460,248 $ 22,361,681 $ 22,367,913 $ 21,351,755 $ 23,369,143 All Sizes $ 744,345,685 $ 743,305,259 $ 640,890,276 $ 850,569,431 $ 27,238,507 $ 27,240,939 $ 26,086,971 $ 28,375,036 Notes: All values in year 2000 dollars.

Detail may not add exactly to totals due to independent rounding.

Derived from LT2ESWTR Cost Model. Median Value Mean Value Median Value Mean Value Economic Analysis for the LT2ESWTR Proposal Q 26 June 2003 Exhibit Q. 25 Treatment Capital and O& M Costs by System Size For Alternative 4  ICRSSL UV90 10 A4 ICRSSL UV90 10 Capital Costs O& M Costs 90 Percent Confidence Bound 90 Percent Confidence Bound System Classification System Size ( population served) Lower ( 5th % tile) Upper ( 95th % tile) Lower ( 5th % tile) Upper ( 95th % tile)

CWSs < 100 $ 471,825 $ 471,924 $ 388,996 $ 554,359 $ 60,129 $ 60,102 $ 56,041 $ 64,213 101 500 $ 1,409,951 $ 1,410,147 $ 1,171,448 $ 1,648,580 $ 172,821 $ 172,753 $ 160,443 $ 185,201 501 1,000 $ 2,019,903 $ 2,020,581 $ 1,728,320 $ 2,310,689 $ 214,052 $ 213,972 $ 200,597 $ 227,711 1,001 3,300 $ 8,542,625 $ 8,543,466 $ 7,275,350 $ 9,806,717 $ 732,584 $ 731,985 $ 681,206 $ 784,442 3,301 10K $ 28,656,819 $ 28,665,242 $ 24,284,879 $ 33,024,238 $ 1,714,980 $ 1,713,391 $ 1,579,961 $ 1,852,920 Small $ 41,101,124 $ 41,111,037 $ 34,873,560 $ 47,326,322 $ 2,894,565 $ 2,892,554 $ 2,680,554 $ 3,112,125 10,001 50K $ 79,498,228 $ 79,509,466 $ 68,631,798 $ 90,437,395 $ 3,874,699 $ 3,874,168 $ 3,719,588 $ 4,031,980 50,001 100K $ 42,333,658 $ 42,332,320 $ 36,393,502 $ 48,321,896 $ 1,993,654 $ 1,993,465 $ 1,925,410 $ 2,062,712 100,001 1M $ 130,884,141 $ 130,881,590 $ 111,667,778 $ 150,256,726 $ 4,271,932 $ 4,272,008 $ 4,103,851 $ 4,440,301 > 1 Million $ 183,668,026 $ 183,708,805 $ 152,598,494 $ 214,824,572 $ 4,929,725 $ 4,930,107 $ 4,610,006 $ 5,250,187 Large $ 436,384,053 $ 436,388,842 $ 369,393,523 $ 503,644,551 $ 15,070,009 $ 15,069,156 $ 14,362,070 $ 15,778,687 CWS Total $ 477,485,177 $ 477,574,892 $ 406,993,215 $ 547,778,225 $ 17,964,574 $ 17,964,524 $ 17,148,013 $ 18,782,714 NTNCWSs < 100 $ 277,998 $ 277,956 $ 229,023 $ 327,800 $ 32,153 $ 32,160 $ 30,000 $ 34,238 101 500 $ 472,976 $ 472,957 $ 396,107 $ 551,084 $ 49,199 $ 49,208 $ 45,764 $ 52,541 501 1,000 $ 339,081 $ 339,139 $ 289,766 $ 389,207 $ 30,752 $ 30,763 $ 28,881 $ 32,608 1,001 3,300 $ 475,466 $ 475,542 $ 409,852 $ 541,935 $ 33,401 $ 33,412 $ 31,064 $ 35,691 3,301 10K $ 385,588 $ 385,644 $ 325,991 $ 446,040 $ 25,057 $ 25,057 $ 22,944 $ 27,130 Small $ 1,951,109 $ 1,951,344 $ 1,652,600 $ 2,254,264 $ 170,562 $ 170,566 $ 158,845 $ 181,934 10,001 50K $ 528,057 $ 527,913 $ 455,145 $ 600,320 $ 23,910 $ 23,908 $ 23,036 $ 24,794 50,001 100K $ 157,004 $ 156,934 $ 133,961 $ 179,896 $ 5,509 $ 5,509 $ 5,314 $ 5,707 100,001 1M $ 253,421 $ 253,359 $ 217,532 $ 289,136 $ 8,766 $ 8,767 $ 8,484 $ 9,054 > 1 Million $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 Large $ 938,483 $ 938,133 $ 806,865 $ 1,068,852 $ 38,185 $ 38,183 $ 36,840 $ 39,548 NTNCWS Total $ 2,889,592 $ 2,887,951 $ 2,528,196 $ 3,252,771 $ 208,747 $ 208,776 $ 196,610 $ 220,678 TNCWSs < 100 $ 1,406,625 $ 1,405,713 $ 1,157,662 $ 1,656,697 $ 158,931 $ 158,918 $ 148,690 $ 169,123 101 500 $ 809,139 $ 808,621 $ 672,820 $ 946,053 $ 86,686 $ 86,675 $ 80,866 $ 92,490 501 1,000 $ 285,522 $ 285,613 $ 244,010 $ 327,396 $ 26,543 $ 26,542 $ 24,939 $ 28,125 1,001 3,300 $ 495,608 $ 495,668 $ 421,252 $ 570,507 $ 40,528 $ 40,529 $ 37,592 $ 43,464 3,301 10K $ 595,146 $ 595,271 $ 503,507 $ 687,533 $ 37,611 $ 37,616 $ 34,489 $ 40,753 Small $ 3,592,041 $ 3,591,709 $ 2,997,835 $ 4,185,977 $ 350,298 $ 350,214 $ 326,975 $ 373,508 10,001 50K $ 538,608 $ 538,157 $ 468,048 $ 609,735 $ 28,697 $ 28,689 $ 27,666 $ 29,723 50,001 100K $ 347,176 $ 346,754 $ 297,705 $ 396,687 $ 14,245 $ 14,243 $ 13,779 $ 14,710 100,001 1M $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 > 1 Million $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 Large $ 885,784 $ 885,026 $ 765,828 $ 1,006,416 $ 42,942 $ 42,931 $ 41,446 $ 44,425 TNCWS Total $ 4,477,825 $ 4,478,309 $ 3,850,196 $ 5,103,613 $ 393,240 $ 393,161 $ 369,329 $ 417,050 All Types < 100 $ 2,156,448 $ 2,156,971 $ 1,890,557 $ 2,425,786 $ 251,212 $ 251,180 $ 239,719 $ 262,760 101 500 $ 2,692,066 $ 2,691,957 $ 2,408,312 $ 2,978,515 $ 308,706 $ 308,724 $ 294,234 $ 323,226 501 1,000 $ 2,644,506 $ 2,644,472 $ 2,345,318 $ 2,943,459 $ 271,347 $ 271,246 $ 257,592 $ 285,268 1,001 3,300 $ 9,513,699 $ 9,512,443 $ 8,244,791 $ 10,782,954 $ 806,513 $ 805,809 $ 755,259 $ 858,838 3,301 10K $ 29,637,553 $ 29,638,734 $ 25,267,710 $ 34,001,104 $ 1,777,648 $ 1,776,009 $ 1,642,400 $ 1,915,351 Small $ 46,644,273 $ 46,641,449 $ 40,392,111 $ 52,905,239 $ 3,415,425 $ 3,412,882 $ 3,199,115 $ 3,635,224 10,001 50K $ 80,564,894 $ 80,576,557 $ 69,698,901 $ 91,507,727 $ 3,927,305 $ 3,926,675 $ 3,772,096 $ 4,084,360 50,001 100K $ 42,837,838 $ 42,840,597 $ 36,900,012 $ 48,814,691 $ 2,013,407 $ 2,013,120 $ 1,945,077 $ 2,082,433 100,001 1M $ 131,137,562 $ 131,136,556 $ 111,915,132 $ 150,514,304 $ 4,280,699 $ 4,280,848 $ 4,112,676 $ 4,449,053 > 1 Million $ 183,668,026 $ 183,708,805 $ 152,598,494 $ 214,824,572 $ 4,929,725 $ 4,930,107 $ 4,610,006 $ 5,250,187 Large $ 438,208,321 $ 438,190,636 $ 371,160,971 $ 505,506,654 $ 15,151,136 $ 15,150,415 $ 14,443,981 $ 15,859,229 All Sizes $ 484,852,594 $ 484,991,206 $ 414,425,039 $ 555,272,015 $ 18,566,561 $ 18,565,170 $ 17,748,041 $ 19,388,565 Notes: All values in year 2000 dollars.

Detail may not add exactly to totals due to independent rounding.

Derived from LT2ESWTR Cost Model. Median Value Mean Value Median Value Mean Value Economic Analysis for the LT2ESWTR Proposal Q 27 June 2003 Exhibit Q. 26 Treatment Capital and O& M Costs by System Size For Alternative 4  ICRSSL UV90 10B A4 ICRSSL UV90 10B Capital Costs O& M Costs 90 Percent Confidence Bound 90 Percent Confidence Bound System Classification System Size ( population served) Lower ( 5th % tile) Upper ( 95th % tile) Lower ( 5th % tile) Upper ( 95th % tile)

CWSs < 100 $ 471,550 $ 471,524 $ 388,119 $ 555,251 $ 60,119 $ 60,117 $ 56,063 $ 64,199 101 500 $ 1,409,375 $ 1,409,965 $ 1,169,040 $ 1,650,148 $ 172,790 $ 172,792 $ 160,515 $ 185,143 501 1,000 $ 2,012,507 $ 2,012,306 $ 1,714,151 $ 2,308,038 $ 213,194 $ 213,216 $ 199,826 $ 226,528 1,001 3,300 $ 8,515,454 $ 8,515,369 $ 7,226,364 $ 9,796,197 $ 730,603 $ 730,418 $ 680,017 $ 781,691 3,301 10K $ 28,607,541 $ 28,618,936 $ 24,161,332 $ 33,039,451 $ 1,713,457 $ 1,713,060 $ 1,579,472 $ 1,848,630 Small $ 41,016,427 $ 41,030,450 $ 34,679,468 $ 47,323,911 $ 2,890,164 $ 2,889,548 $ 2,678,017 $ 3,103,842 10,001 50K $ 80,675,846 $ 80,722,858 $ 69,464,016 $ 91,754,447 $ 3,926,959 $ 3,927,288 $ 3,772,716 $ 4,081,308 50,001 100K $ 43,093,702 $ 43,123,870 $ 36,960,458 $ 49,127,784 $ 2,030,892 $ 2,031,165 $ 1,962,417 $ 2,099,686 100,001 1M $ 133,473,683 $ 133,496,127 $ 113,617,802 $ 153,046,593 $ 4,405,944 $ 4,406,569 $ 4,235,419 $ 4,577,047 > 1 Million $ 185,077,014 $ 185,177,004 $ 153,234,843 $ 216,588,021 $ 5,004,988 $ 5,006,179 $ 4,685,878 $ 5,323,109 Large $ 442,320,246 $ 442,457,999 $ 373,340,614 $ 510,369,902 $ 15,368,782 $ 15,371,412 $ 14,660,275 $ 16,074,780 CWS Total $ 483,336,672 $ 483,339,126 $ 411,303,254 $ 554,864,905 $ 18,258,946 $ 18,259,745 $ 17,444,600 $ 19,069,564 NTNCWSs < 100 $ 278,208 $ 278,440 $ 229,242 $ 326,604 $ 32,169 $ 32,160 $ 30,053 $ 34,254 101 500 $ 473,260 $ 474,022 $ 396,099 $ 550,022 $ 49,226 $ 49,215 $ 45,874 $ 52,525 501 1,000 $ 337,756 $ 337,902 $ 289,312 $ 386,744 $ 30,571 $ 30,577 $ 28,759 $ 32,360 1,001 3,300 $ 475,460 $ 475,824 $ 410,666 $ 540,472 $ 33,294 $ 33,311 $ 31,012 $ 35,527 3,301 10K $ 385,039 $ 385,381 $ 326,020 $ 443,803 $ 25,055 $ 25,064 $ 22,996 $ 27,076 Small $ 1,949,724 $ 1,951,667 $ 1,653,973 $ 2,245,195 $ 170,315 $ 170,336 $ 158,889 $ 181,399 10,001 50K $ 537,368 $ 537,405 $ 464,278 $ 609,520 $ 24,352 $ 24,355 $ 23,462 $ 25,235 50,001 100K $ 160,855 $ 160,882 $ 137,819 $ 183,639 $ 5,703 $ 5,705 $ 5,499 $ 5,904 100,001 1M $ 259,462 $ 259,478 $ 223,497 $ 295,053 $ 9,086 $ 9,088 $ 8,788 $ 9,384 > 1 Million $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 Large $ 957,685 $ 957,913 $ 825,946 $ 1,088,152 $ 39,142 $ 39,151 $ 37,759 $ 40,518 NTNCWS Total $ 2,907,409 $ 2,910,128 $ 2,553,401 $ 3,263,878 $ 209,456 $ 209,422 $ 197,524 $ 221,062 TNCWSs < 100 $ 1,404,899 $ 1,405,593 $ 1,151,699 $ 1,652,244 $ 158,917 $ 158,961 $ 148,514 $ 169,007 101 500 $ 808,056 $ 808,382 $ 669,922 $ 943,417 $ 86,677 $ 86,707 $ 80,773 $ 92,382 501 1,000 $ 283,922 $ 283,841 $ 241,889 $ 325,382 $ 26,377 $ 26,391 $ 24,753 $ 27,940 1,001 3,300 $ 494,827 $ 494,673 $ 419,370 $ 569,039 $ 40,397 $ 40,411 $ 37,441 $ 43,307 3,301 10K $ 593,242 $ 593,021 $ 500,223 $ 684,205 $ 37,568 $ 37,588 $ 34,446 $ 40,684 Small $ 3,584,946 $ 3,585,198 $ 2,982,978 $ 4,175,667 $ 349,936 $ 350,126 $ 326,461 $ 372,944 10,001 50K $ 546,872 $ 546,730 $ 474,977 $ 618,728 $ 29,128 $ 29,129 $ 28,101 $ 30,156 50,001 100K $ 354,486 $ 354,424 $ 304,454 $ 404,470 $ 14,655 $ 14,659 $ 14,183 $ 15,128 100,001 1M $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 > 1 Million $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 Large $ 901,358 $ 901,167 $ 779,803 $ 1,023,216 $ 43,783 $ 43,787 $ 42,286 $ 45,284 TNCWS Total $ 4,486,304 $ 4,488,500 $ 3,856,528 $ 5,106,877 $ 393,719 $ 393,824 $ 369,465 $ 417,243 All Types < 100 $ 2,154,657 $ 2,154,161 $ 1,888,272 $ 2,416,009 $ 251,204 $ 251,308 $ 239,625 $ 262,455 101 500 $ 2,690,691 $ 2,692,422 $ 2,404,374 $ 2,976,552 $ 308,693 $ 308,706 $ 294,432 $ 322,758 501 1,000 $ 2,634,185 $ 2,634,462 $ 2,328,172 $ 2,939,749 $ 270,142 $ 270,219 $ 256,450 $ 283,700 1,001 3,300 $ 9,485,742 $ 9,486,200 $ 8,198,403 $ 10,778,763 $ 804,294 $ 804,333 $ 753,444 $ 855,522 3,301 10K $ 29,585,821 $ 29,593,663 $ 25,142,872 $ 34,020,015 $ 1,776,081 $ 1,775,855 $ 1,642,164 $ 1,911,317 Small $ 46,551,096 $ 46,552,537 $ 40,178,467 $ 52,950,516 $ 3,410,414 $ 3,410,400 $ 3,194,962 $ 3,625,917 10,001 50K $ 81,760,086 $ 81,794,018 $ 70,560,968 $ 92,824,435 $ 3,980,439 $ 3,980,817 $ 3,826,360 $ 4,135,007 50,001 100K $ 43,609,043 $ 43,636,283 $ 37,458,619 $ 49,641,339 $ 2,051,249 $ 2,051,528 $ 1,982,715 $ 2,119,981 100,001 1M $ 133,733,146 $ 133,768,132 $ 113,881,602 $ 153,314,347 $ 4,415,030 $ 4,415,697 $ 4,244,497 $ 4,585,984 > 1 Million $ 185,077,014 $ 185,177,004 $ 153,234,843 $ 216,588,021 $ 5,004,988 $ 5,006,179 $ 4,685,878 $ 5,323,109 Large $ 444,179,289 $ 444,309,432 $ 375,243,826 $ 512,200,391 $ 15,451,707 $ 15,454,618 $ 14,743,605 $ 16,158,193 All Sizes $ 490,730,385 $ 490,752,447 $ 418,785,605 $ 562,345,472 $ 18,862,121 $ 18,864,304 $ 18,049,740 $ 19,671,674 Notes: All values in year 2000 dollars.

Detail may not add exactly to totals due to independent rounding.

Derived from LT2ESWTR Cost Model. Median Value Mean Value Median Value Mean Value Economic Analysis for the LT2ESWTR Proposal Q 28 June 2003 Exhibit Q. 27 Treatment Capital and O& M Costs by System Size For Alternative 4  ICRSSM UV90 10 A4 ICRSSM UV90 10 Capital Costs O& M Costs 90 Percent Confidence Bound 90 Percent Confidence Bound System Classification System Size ( population served) Lower ( 5th % tile) Upper ( 95th % tile) Lower ( 5th % tile) Upper ( 95th % tile)

CWSs < 100 $ 343,258 $ 343,092 $ 282,673 $ 403,963 $ 44,547 $ 44,543 $ 41,550 $ 47,537 101 500 $ 1,051,750 $ 1,051,221 $ 871,340 $ 1,231,899 $ 132,920 $ 132,908 $ 123,422 $ 142,399 501 1,000 $ 1,612,697 $ 1,612,634 $ 1,378,537 $ 1,848,759 $ 175,997 $ 175,996 $ 164,850 $ 187,047 1,001 3,300 $ 6,718,495 $ 6,718,427 $ 5,722,063 $ 7,724,691 $ 579,400 $ 579,359 $ 538,866 $ 619,969 3,301 10K $ 23,159,695 $ 23,160,613 $ 19,575,563 $ 26,752,535 $ 1,351,617 $ 1,351,548 $ 1,245,779 $ 1,458,079 Small $ 32,885,895 $ 32,885,640 $ 27,842,878 $ 37,951,061 $ 2,284,481 $ 2,284,162 $ 2,116,105 $ 2,453,276 10,001 50K $ 57,350,642 $ 57,309,868 $ 49,476,325 $ 65,286,832 $ 2,886,178 $ 2,885,627 $ 2,770,105 $ 3,002,101 50,001 100K $ 30,151,437 $ 30,120,006 $ 25,892,186 $ 34,432,077 $ 1,488,725 $ 1,488,632 $ 1,438,038 $ 1,539,251 100,001 1M $ 95,227,669 $ 95,131,108 $ 81,044,751 $ 109,365,114 $ 3,203,345 $ 3,202,612 $ 3,075,498 $ 3,330,912 > 1 Million $ 166,356,520 $ 166,381,565 $ 137,675,524 $ 194,991,958 $ 4,483,755 $ 4,483,112 $ 4,187,980 $ 4,778,609 Large $ 349,086,267 $ 348,878,155 $ 294,191,616 $ 404,097,533 $ 12,062,003 $ 12,060,660 $ 11,473,752 $ 12,648,371 CWS Total $ 381,972,162 $ 381,813,171 $ 324,194,232 $ 439,860,154 $ 14,346,484 $ 14,346,269 $ 13,666,983 $ 15,021,657 NTNCWSs < 100 $ 200,599 $ 200,193 $ 165,176 $ 235,955 $ 23,152 $ 23,151 $ 21,639 $ 24,666 101 500 $ 341,234 $ 340,846 $ 285,328 $ 397,642 $ 35,429 $ 35,427 $ 33,007 $ 37,823 501 1,000 $ 243,811 $ 243,521 $ 208,300 $ 279,722 $ 22,064 $ 22,059 $ 20,739 $ 23,383 1,001 3,300 $ 344,038 $ 343,582 $ 296,432 $ 391,240 $ 24,000 $ 23,998 $ 22,339 $ 25,656 3,301 10K $ 277,627 $ 277,304 $ 234,525 $ 320,876 $ 18,035 $ 18,033 $ 16,538 $ 19,518 Small $ 1,407,309 $ 1,406,270 $ 1,191,438 $ 1,624,827 $ 122,681 $ 122,661 $ 114,313 $ 130,880 10,001 50K $ 345,570 $ 345,629 $ 298,468 $ 392,523 $ 16,885 $ 16,883 $ 16,294 $ 17,471 50,001 100K $ 102,203 $ 102,235 $ 87,378 $ 117,033 $ 3,884 $ 3,884 $ 3,752 $ 4,016 100,001 1M $ 166,195 $ 166,233 $ 142,880 $ 189,455 $ 6,156 $ 6,156 $ 5,966 $ 6,346 > 1 Million $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 Large $ 613,967 $ 614,130 $ 528,739 $ 699,054 $ 26,925 $ 26,922 $ 26,013 $ 27,827 NTNCWS Total $ 2,021,276 $ 2,019,194 $ 1,765,157 $ 2,273,027 $ 149,606 $ 149,601 $ 141,015 $ 158,166 TNCWSs < 100 $ 1,010,160 $ 1,010,089 $ 829,053 $ 1,189,346 $ 114,640 $ 114,601 $ 107,171 $ 122,028 101 500 $ 581,107 $ 581,205 $ 483,004 $ 678,536 $ 62,532 $ 62,522 $ 58,292 $ 66,704 501 1,000 $ 204,497 $ 204,588 $ 174,242 $ 234,710 $ 19,078 $ 19,083 $ 17,927 $ 20,217 1,001 3,300 $ 357,314 $ 357,353 $ 303,031 $ 411,254 $ 29,177 $ 29,192 $ 27,071 $ 31,244 3,301 10K $ 426,741 $ 426,676 $ 359,978 $ 492,767 $ 27,108 $ 27,115 $ 24,868 $ 29,311 Small $ 2,579,818 $ 2,579,503 $ 2,150,402 $ 3,004,547 $ 252,535 $ 252,491 $ 235,611 $ 268,976 10,001 50K $ 353,429 $ 353,231 $ 307,148 $ 399,498 $ 20,353 $ 20,349 $ 19,652 $ 21,045 50,001 100K $ 226,496 $ 226,368 $ 194,523 $ 258,572 $ 10,158 $ 10,158 $ 9,841 $ 10,472 100,001 1M $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 > 1 Million $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 Large $ 579,925 $ 579,658 $ 501,946 $ 658,221 $ 30,511 $ 30,508 $ 29,496 $ 31,515 TNCWS Total $ 3,159,743 $ 3,159,593 $ 2,713,444 $ 3,606,340 $ 283,046 $ 282,990 $ 265,682 $ 299,891 All Types < 100 $ 1,554,016 $ 1,555,706 $ 1,362,145 $ 1,744,195 $ 182,340 $ 182,336 $ 174,045 $ 190,553 101 500 $ 1,974,090 $ 1,974,368 $ 1,760,335 $ 2,187,396 $ 230,880 $ 230,873 $ 219,812 $ 241,652 501 1,000 $ 2,061,005 $ 2,061,441 $ 1,820,247 $ 2,304,639 $ 217,139 $ 217,144 $ 205,728 $ 228,394 1,001 3,300 $ 7,419,847 $ 7,418,520 $ 6,415,522 $ 8,429,677 $ 632,577 $ 632,537 $ 591,985 $ 673,035 3,301 10K $ 23,864,063 $ 23,863,799 $ 20,281,561 $ 27,447,902 $ 1,396,760 $ 1,396,623 $ 1,290,861 $ 1,502,912 Small $ 36,873,022 $ 36,878,627 $ 31,780,251 $ 41,974,437 $ 2,659,696 $ 2,659,511 $ 2,489,649 $ 2,829,622 10,001 50K $ 58,049,641 $ 58,012,543 $ 50,170,138 $ 65,996,499 $ 2,923,417 $ 2,922,895 $ 2,807,232 $ 3,039,465 50,001 100K $ 30,480,136 $ 30,450,929 $ 26,226,048 $ 34,765,990 $ 1,502,767 $ 1,502,696 $ 1,452,200 $ 1,553,287 100,001 1M $ 95,393,864 $ 95,303,545 $ 81,211,332 $ 109,546,889 $ 3,209,501 $ 3,208,772 $ 3,081,600 $ 3,337,021 > 1 Million $ 166,356,520 $ 166,381,565 $ 137,675,524 $ 194,991,958 $ 4,483,755 $ 4,483,112 $ 4,187,980 $ 4,778,609 Large $ 350,280,160 $ 350,067,994 $ 295,393,316 $ 405,290,248 $ 12,119,439 $ 12,117,835 $ 11,531,292 $ 12,706,091 All Sizes $ 387,153,182 $ 387,013,138 $ 329,339,619 $ 445,012,956 $ 14,779,135 $ 14,778,748 $ 14,098,726 $ 15,452,556 Notes: All values in year 2000 dollars.

Detail may not add exactly to totals due to independent rounding.

Derived from LT2ESWTR Cost Model. Median Value Mean Value Median Value Mean Value Economic Analysis for the LT2ESWTR Proposal Q 29 June 2003 Exhibit Q. 28 Treatment Capital and O& M Costs by System Size For Alternative 4  ICRSSM UV90 10B A4 ICRSSM UV90 10B Capital Costs O& M Costs 90 Percent Confidence Bound 90 Percent Confidence Bound System Classification System Size ( population served) Lower ( 5th % tile) Upper ( 95th % tile) Lower ( 5th % tile) Upper ( 95th % tile)

CWSs < 100 $ 343,258 $ 343,092 $ 282,673 $ 403,963 $ 44,547 $ 44,543 $ 41,550 $ 47,537 101 500 $ 1,051,750 $ 1,051,221 $ 871,340 $ 1,231,899 $ 132,920 $ 132,908 $ 123,422 $ 142,399 501 1,000 $ 1,604,338 $ 1,604,225 $ 1,370,341 $ 1,840,359 $ 175,399 $ 175,405 $ 164,293 $ 186,441 1,001 3,300 $ 6,687,967 $ 6,688,560 $ 5,690,663 $ 7,694,056 $ 577,708 $ 577,661 $ 537,184 $ 618,277 3,301 10K $ 23,096,031 $ 23,097,124 $ 19,508,089 $ 26,690,106 $ 1,349,239 $ 1,349,176 $ 1,243,390 $ 1,455,703 Small $ 32,783,344 $ 32,782,476 $ 27,737,618 $ 37,850,682 $ 2,279,814 $ 2,279,475 $ 2,111,255 $ 2,448,484 10,001 50K $ 57,894,660 $ 57,847,023 $ 50,004,543 $ 65,838,544 $ 2,910,591 $ 2,910,232 $ 2,794,569 $ 3,026,586 50,001 100K $ 30,496,860 $ 30,471,410 $ 26,240,129 $ 34,774,319 $ 1,506,106 $ 1,506,009 $ 1,455,075 $ 1,557,050 100,001 1M $ 96,409,787 $ 96,318,378 $ 82,201,166 $ 110,554,200 $ 3,267,372 $ 3,267,034 $ 3,136,812 $ 3,397,102 > 1 Million $ 166,974,995 $ 166,988,631 $ 138,279,941 $ 195,605,080 $ 4,520,463 $ 4,519,880 $ 4,222,949 $ 4,817,033 Large $ 351,776,303 $ 351,607,524 $ 296,865,498 $ 406,712,368 $ 12,204,533 $ 12,202,327 $ 11,612,970 $ 12,793,399 CWS Total $ 384,559,647 $ 384,429,647 $ 326,735,635 $ 442,494,166 $ 14,484,347 $ 14,484,928 $ 13,800,968 $ 15,162,758 NTNCWSs < 100 $ 200,130 $ 200,234 $ 164,373 $ 235,448 $ 23,148 $ 23,141 $ 21,623 $ 24,664 101 500 $ 340,539 $ 340,551 $ 283,955 $ 396,037 $ 35,422 $ 35,414 $ 32,995 $ 37,833 501 1,000 $ 241,441 $ 241,394 $ 205,299 $ 276,807 $ 21,922 $ 21,915 $ 20,615 $ 23,235 1,001 3,300 $ 341,922 $ 341,945 $ 293,604 $ 389,632 $ 23,887 $ 23,881 $ 22,244 $ 25,526 3,301 10K $ 275,848 $ 275,778 $ 232,228 $ 318,772 $ 17,982 $ 17,983 $ 16,479 $ 19,467 Small $ 1,399,880 $ 1,399,610 $ 1,180,451 $ 1,615,415 $ 122,361 $ 122,329 $ 114,105 $ 130,495 10,001 50K $ 350,268 $ 350,459 $ 303,724 $ 397,442 $ 17,098 $ 17,097 $ 16,514 $ 17,687 50,001 100K $ 104,106 $ 104,183 $ 89,400 $ 118,965 $ 3,977 $ 3,977 $ 3,845 $ 4,110 100,001 1M $ 169,214 $ 169,298 $ 146,126 $ 192,468 $ 6,311 $ 6,310 $ 6,121 $ 6,504 > 1 Million $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 Large $ 623,589 $ 623,808 $ 539,277 $ 709,013 $ 27,386 $ 27,383 $ 26,480 $ 28,302 NTNCWS Total $ 2,023,469 $ 2,023,239 $ 1,764,174 $ 2,277,521 $ 149,748 $ 149,672 $ 141,212 $ 158,230 TNCWSs < 100 $ 1,010,160 $ 1,010,089 $ 829,053 $ 1,189,346 $ 114,640 $ 114,601 $ 107,171 $ 122,028 101 500 $ 581,107 $ 581,205 $ 483,004 $ 678,536 $ 62,532 $ 62,522 $ 58,292 $ 66,704 501 1,000 $ 202,844 $ 202,912 $ 172,522 $ 232,958 $ 18,959 $ 18,963 $ 17,811 $ 20,094 1,001 3,300 $ 355,428 $ 355,478 $ 301,054 $ 409,310 $ 29,055 $ 29,071 $ 26,950 $ 31,118 3,301 10K $ 424,859 $ 424,835 $ 358,107 $ 490,779 $ 27,042 $ 27,050 $ 24,800 $ 29,243 Small $ 2,574,397 $ 2,574,037 $ 2,145,186 $ 2,998,382 $ 252,228 $ 252,185 $ 235,311 $ 268,675 10,001 50K $ 357,894 $ 357,663 $ 311,610 $ 403,926 $ 20,551 $ 20,549 $ 19,849 $ 21,244 50,001 100K $ 230,229 $ 230,096 $ 198,195 $ 262,288 $ 10,349 $ 10,350 $ 10,024 $ 10,668 100,001 1M $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 > 1 Million $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 Large $ 588,123 $ 587,652 $ 510,017 $ 666,134 $ 30,900 $ 30,900 $ 29,876 $ 31,912 TNCWS Total $ 3,162,520 $ 3,162,680 $ 2,716,422 $ 3,609,587 $ 283,128 $ 283,064 $ 265,779 $ 299,963 All Types < 100 $ 1,553,548 $ 1,554,655 $ 1,358,228 $ 1,749,116 $ 182,336 $ 182,337 $ 174,039 $ 190,635 101 500 $ 1,973,395 $ 1,973,569 $ 1,757,434 $ 2,187,011 $ 230,873 $ 230,873 $ 219,964 $ 241,719 501 1,000 $ 2,048,623 $ 2,047,887 $ 1,806,717 $ 2,292,423 $ 216,280 $ 216,269 $ 204,897 $ 227,542 1,001 3,300 $ 7,385,317 $ 7,384,349 $ 6,379,541 $ 8,392,480 $ 630,650 $ 630,642 $ 589,989 $ 671,102 3,301 10K $ 23,796,739 $ 23,799,446 $ 20,210,092 $ 27,384,128 $ 1,394,264 $ 1,394,175 $ 1,288,187 $ 1,500,535 Small $ 36,757,622 $ 36,758,429 $ 31,677,649 $ 41,853,064 $ 2,654,404 $ 2,653,658 $ 2,484,201 $ 2,823,877 10,001 50K $ 58,602,823 $ 58,558,358 $ 50,722,606 $ 66,552,641 $ 2,948,240 $ 2,947,804 $ 2,832,167 $ 3,064,127 50,001 100K $ 30,831,195 $ 30,809,650 $ 26,571,929 $ 35,106,847 $ 1,520,431 $ 1,520,284 $ 1,469,517 $ 1,571,430 100,001 1M $ 96,579,001 $ 96,490,941 $ 82,355,222 $ 110,716,418 $ 3,273,684 $ 3,273,352 $ 3,143,093 $ 3,403,396 > 1 Million $ 166,974,995 $ 166,988,631 $ 138,279,941 $ 195,605,080 $ 4,520,463 $ 4,519,880 $ 4,222,949 $ 4,817,033 Large $ 352,988,014 $ 352,814,971 $ 298,063,345 $ 407,914,359 $ 12,262,819 $ 12,260,445 $ 11,671,348 $ 12,851,390 All Sizes $ 389,745,636 $ 389,614,562 $ 331,928,139 $ 447,656,152 $ 14,917,222 $ 14,916,871 $ 14,232,219 $ 15,596,505 Notes: All values in year 2000 dollars.

Detail may not add exactly to totals due to independent rounding.

Derived from LT2ESWTR Cost Model. Median Value Mean Value Median Value Mean Value Economic Analysis for the LT2ESWTR Proposal Q 30 June 2003 1 The estimate of deaths in 1999 of persons with AIDS used in this EA is from the 1999 year end HIV/ AIDS Surveillance Report ( Vol 11, No. 2), and the estimate of the population of persons living with AIDS is from the supplemental report on " Characteristics of Persons Living With AIDS at the End of 1999." ( Vol 7, No. 1). CDC recently released revised data for 1999 and data for 2000. The potential impact of these changes is discussed in sections R. 2 and R. 5.

Economic Analysis for the LT2ESWTR Proposal R 1 June 2003 Appendix R Sensitivity Analysis for AIDS Related Mortality Rate R. 1 Introduction and Summary A key input to the Long Term 2 Enhanced Surface Water Treatment Rule ( LT2ESWTR) risk assessment model is the rate of mortality associated with cryptosporidiosis. This is discussed in section 5.2.3 ( Dose Response Assessment). The mortality rate as used in this analysis is, given a case of cryptosporidiosis, the probability of a fatality from that illness. As discussed in section 5.2.3, the risk assessment model uses different mortality rates for those with AIDS and the general populations.

Cryptosporidiosis is considered nonfatal in healthy adults, so the mortality rate in the general, non AIDS, population represents deaths for those with other conditions or diseases that hinder recovery from cryptosporidiosis. The mortality rate used for the general population is the mortality rate associated with the 1993 Milwaukee Cryptosporidium outbreak for those without AIDS. This rate is used as an estimate of the mortality rate for future cryptosporidiosis cases because no significant treatments that would likely lessen mortality have been developed since then.

Data from the 1993 Milwaukee cryptosporidiosis outbreak are also used to develop the mortality rate for people with AIDS. However, for those with AIDS, new treatments have become available since the Milwaukee outbreak that greatly prolong life. As a result of the advent of highly active anti retroviral therapy ( HAART) in 1995, the rate of death for those with AIDS from all causes has declined dramatically. The Dose Response Assessment includes a factor to reflect the apparent lessened mortality among persons with AIDS. Data from the Centers for Disease Control and Prevention ( CDC) for 1993 and 19991 suggest that, among those with AIDS, the death rate for all reasons in 1999 was only 12.3 percent of the rate in 1993, the year of the Milwaukee outbreak. To reflect the probable improved ability of those with AIDS to survive cryptosporidiosis, the mortality rate for those with AIDS during the Milwaukee outbreak was adjusted by this factor and applied to each year of the 25 year analysis without change ( that is, without allowing for further changes in mortality rates). This no trend approach is considered a reasonable best estimate, given the difficulty of predicting future trends in AIDS related mortality, including the lack of cryptosporidiosis specific information.

This appendix presents the latest AIDS related mortality data available from the CDC, summarizes the history of AIDS related mortality, provides information regarding the factors that may affect future AIDS related mortality, and discusses the potential impact on the LT2ESWTR benefits analysis results of using the latest estimates from CDC and other mortality rates ( arbitrarily bounded) to Economic Analysis for the LT2ESWTR Proposal R 2 June 2003 reflect at least some of the range of possible values that may develop in future years. This appendix does not discuss other related assumptions, such as the constant ratio of persons living with AIDS to the general population used in the model and the mortality rates for the general population.

The impact of using the latest data from CDC is that using CDC's revised data for 1999 would raise the mortality rate for those with AIDS by half ( a 50 percent increase), and raise the total estimate of mean benefits by about a fifth ( 20 percent). Using the CDC's estimate for 2000 would reduce the AIDSrelated mortality rate by 14 percent, and the overall level of mean benefits by 8 percent. Although CDC has tried to adjust this initial 2000 estimate for potential delays in reporting, the estimate is likely to be revised in subsequent years, and may well be higher than this initial estimate ( for example, data for 1999 increased by 50 percent). Using either of these new estimates from CDC would not have changed the conclusions of the EA or the selection of the Preferred Alternative.

The review of the confounding factors that influence the future mortality of those with AIDS gave no definite direction of future change ( that the rate will definitely increase or definitely decrease). The bounding analysis, presented below, assessed the impact on LT2ESWTR benefits due to the AIDSrelated mortality rate either increasing or decreasing. This analysis was done by arbitrarily doubling and halving the 1999 rate used in the economic analysis ( EA) and, as in the EA analysis, assuming a constant mortality rate over the period of the analysis.

The results of the bounding analysis indicate that doubling the AIDS related mortality rate would result in mean total benefits 41 percent higher, and no change in the conclusion of the EA or selection of the Preferred Alternative. The result of halving the AIDS related mortality rate would be a mean total benefits estimate 24 percent lower than used in the EA. This reduction, if considered alone, would significantly improve the relative standing of Alternative A4, making it essentially equal to the Preferred Alternative. However, accounting for unquantified benefits, which are described in section 5.4, would favor the Preferred Alternative. In summary, given the likelihood that increases in the AIDS mortality rate are at least as likely as decreases, and that unquantified benefits exist, the conclusions of the EA and the selection of the Preferred Alternative are not challenged.

R. 2 Latest CDC Data and Their Impact on the AIDS Mortality Adjustment Factor The adjustment factor for AIDS related mortality used in the Dose Response Assessment is computed from both death and population data. The EA uses 1999 data on the number of AIDS deaths as cited in CDC's 1999 end of year HIV/ AIDS Surveillance Report. CDC has revised the 1999 estimate upward by 50 percent in the 2000 end of year report ( the latest available). This latter report also provides initial data for 2000, which are slightly lower than the initial ( 1999) values used in this EA ( both are shown in Exhibit R. 1). The initial estimate for 2000 is based on actual reported data and is adjusted to account for projected delays in reporting. The CDC released revised estimates for the number of persons living with AIDS in 1999 in a supplement to the 1999 end of year surveillance report. In CDC's end of year 2000 report, CDC did not provide a revised estimate for persons living with AIDS in 1999. Economic Analysis for the LT2ESWTR Proposal R 3 June 2003 Exhibit R. 1 Mortality Rate Factors Using Latest CDC Data 1993 Initial 1999 Revised 1999 Initial 2000 AIDS Deaths 45,271 10,122 15,254 8,911 Persons Living with AIDS 174,369 317,652 317,652 322,865 Mortality Rate ( per 100,000) 25,963 3,187 4,802 2,760 Mortality Rate as a Percent of 1993 12.3% 18.5% 10.6%

Source: CDC's end of year HIV/ AIDS Surveillance Reports for 1999 and 2000 ( Vol. 11, No. 2 and Vol. 3, No. 1), and the Supplement to the 1999 report. Note: A revised Persons Living with AIDS estimate for 1999 was not reported in CDC's end of year 2000 HIV/ AIDS Surveillance Report. However, if the increase in deaths were subtracted from the population of persons living with AIDS, a revised number might be 312,794 ( that is, 317,652  4,802), and the mortality rate percentage would then be 18.8 percent.

The revised estimate for the AIDS mortality rate in 1999 is 50 percent higher than previously reported, and the newly released estimate for 2000 would imply a factor of 10.6 percent rather than the 12.3 percent used in the analysis. ( The impacts of these differences will be discussed in section R. 5.) The 2000 estimate will likely be revised in subsequent years as more data become available. The apparent 43 percent drop from 1999 ( revised) ( 18.5 percent) to 2000 ( 10.6 percent) may be less indicative of the historical trend than the differences between 1999 and 1998, which are based on more complete data rather than estimates.

R. 3 History of AIDS Related Mortality Rates Over roughly the past decade, the AIDS related mortality rate has been declining. This decline has resulted from both a decrease in the number of AIDS related deaths and an increase in the number of people living with AIDS. However, the decline in AIDS related deaths has slowed somewhat in recent years.

Decline in AIDS Related Deaths Due to Use of HAART Data show that AIDS related deaths declined as people with AIDS began using HAART, which became available in 1995 and appears to be successful in significantly prolonging the lives of persons with AIDS. Since the introduction of HAART, treatment has become available to almost all people in the United States with known cases of AIDS ( Boyle 2002). The result, at least in the short term, is a reduction in the numbers of deaths of persons with AIDS ( Exhibit R. 2). With the availability of the treatment now nearly universal in the United States, the reduction in the number of deaths is slowing after the steep declines seen in 1996 and the first half of 1997. This observation derives from Karon et al. Economic Analysis for the LT2ESWTR Proposal R 4 June 2003 ( 2001), who adjusted their data for delayed reporting and characterized the quarterly mortality rate during 1998 and 1999 as " approximately constant." ( Their study did not include 2000 data.)

Exhibit R. 2 AIDS Cases and Deaths Among Adults and Adolescents in the United States, by Quarter Year, 1990 1999 1 Source: http:// www. cdc. gov/ hiv/ stats/ hasrsupp81/ fig3. htm The initial estimate for 2000 appears to show a continued slight decline. However, in previous reports from the CDC ( HIV/ AIDS Surveillance Reports), early results have been revised upward in later reports as additional data became available. Whether the number of deaths has continued its slight decline or leveled off cannot be determined reliably from the available data.

Declining New AIDS Cases; Increases in Number of People Living With AIDS In addition to the decline in AIDS related deaths, new cases of AIDS also declined because of HIV treatments; but more people are living with AIDS. Exhibit R. 2 shows the trend in new cases ( incidence) of AIDS being reported. The number of new cases is most directly affected by the effectiveness of treatments, including HAART, that prevent the shift from HIV infection to clinical cases Economic Analysis for the LT2ESWTR Proposal R 5 June 2003 0% 3% 6% 9% 12% 15% 18% 21% 24% 27% 30%

1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 Deaths as a Percent of Population Living With AIDS Based on death data from EOY 1999 Report Based on death data from EOY 2000 Report of AIDS. Those declines have also leveled off and there appears to be only a 2 3 percent decline from 1998 to 1999. CDC characterizes the trend in the number of new AIDS cases as appearing " to be leveling" ( http:// www. cdc. gov/ nchstp/ od/ news/ At a Glance. pdf) and Karon et al. ( 2001) described it as " relatively constant."

The population of persons living with AIDS has continued to grow as new cases are identified and fewer people die from the disease and its complications. The annual increase from 1998 to 2000 was 18 percent and the total number of persons living with AIDS is estimated at 322,865 in 2000 ( CDC, 2000).

Overall Effect on AIDS Mortality Rates Data show that the overall AIDS mortality rate continues to decline, but that the decline is slowing ( Exhibit R. 3). The mortality rates used in the EA benefits model are computed from both death and population data. Because the underlying data on deaths have been revised in the end of year 2000 Surveillance Report, the mortality rates based on these data are also shown. However, because the 2000 estimate will likely be revised in subsequent years, the apparent 43 percent drop in AIDS mortality from 1999 ( revised) to 2000 may be less indicative of the historical trend than the differences between 1999 and 1998.

Exhibit R. 3 AIDS Related Death Rates, 1993 to 2000 Source: Derived from CDC end of year HIV/ AIDS Surveillance Reports for 1999 and 2000 ( data on deaths), and the supplement to the 1999 report ( data on persons living with AIDS). Economic Analysis for the LT2ESWTR Proposal R 6 June 2003 R. 4 Factors Affecting Mortality in the Future Statistical Shift Over Time Several factors affect the mortality rate of persons with AIDS. One ( identified earlier) is that life prolonging treatments are widely available and used. However, the rapid decline in mortality rates that accompanied their introduction may be temporary. HAART is not considered a cure for AIDS. If the only effect is increased longevity, but with a similar pattern of eventual disease, those who are now less susceptible would become susceptible again in the future. In such a case, the mortality rate could conceivably climb to near historical levels. The reason it would be unlikely to fully reach historical levels is that the longer the increased longevity, the more likely it is that deaths would occur for reasons other than AIDS. This reasoning suggests that, with all other influences equal ( which they are not), the mortality rate would lessen for a period roughly corresponding to increased longevity, then increase to some new level. Many other factors are also important, however.

Drug Resistance History supports a view that infectious disease mortality initially drops considerably upon the introduction of successful treatment, but after a lag the mortality rate stabilizes or slightly increases as drug resistance and other factors counteract the benefit of treatment. The treatment of tuberculosis ( TB) after World War II with streptomycin had immediate success, but within a few months drug resistance began to show. Physicians were able to develop additional antibiotics, and TB was treated using a multiple drug regimen ( NJMS 1996). The mortality rate for tuberculosis in industrialized countries had been declining slowly until the mid 1980s, when the mortality rate stabilized and more recently has increased slightly ( NJMS 1996). Some similar patterns are beginning to be identified with AIDS.

Drug resistance to AIDS therapies is, in fact, increasing. If a patient develops a drug resistant strain of HIV, treatment becomes difficult. If new regimens cannot be developed for this individual, the disease will proceed as it did prior to treatment, and result in AIDS related death. Forty nine percent of individuals with HIV have drug resistant strains ( Brown 2001). Among those HIV individuals who have not started treatment, 20 percent have a strain resistant to at least one drug, an increase from 3 to 5 percent of new cases several years ago ( Brown 2001). Because the therapies for HIV and AIDS are essentially the same, this suggests that those who progress from HIV to AIDS are increasingly likely to have drug resistant strains. As the proportion of persons with drug resistant strains increases within the population of those living with AIDS, this would be an upward influence on the AIDS mortality rate.

Side Effects Leading to Cessation of Treatment Another factor that may affect mortality is the cessation of therapy due to intolerable side effects. Over time, the side effects from drug therapy ( such as diarrhea, peripheral neuropathy, severe rash, jaundice, pancreatitis, kidney stones, and others) become too painful or uncomfortable for many people to bear ( Highleyman 2000, NYSDHAI 2002, Griffiths 2002). The number of patients that will drop treatment in the coming years due to side effects is therefore likely to increase ( NYSDHAI 2002). Studies show that relapse is rapid after cessation of therapy; among those tested who had no detectable virus in their system, the time to relapse to pre treatment levels of virus in the blood ranged from 4 to 31 days, with most relapsing within 2 to 3 weeks after ceasing therapy ( Marble 2000, Medscape 2002). Even for those patients who had been treated for over 2 years, relapse occurred promptly after cessation of therapy ( Medscape 2002). If a treatment regimen cannot be developed that reduces side effects to Economic Analysis for the LT2ESWTR Proposal R 7 June 2003 tolerable levels, some patients will likely quit treatment, and their mortality rate from various sources, including cryptosporidiosis, would increase. Over time, as more people with AIDS develop these intolerable side effects and cease treatment, the overall AIDS mortality rate would also increase.

Mortality from Side Effects The previous factors that may affect mortality would increase the mortality rate, and are assumed to have a parallel effect on deaths from cryptosporidiosis in persons with AIDS. There is one factor, however, that may increase mortality among persons with AIDS, but not the mortality from cryptosporidiosis. Among the side effects of HAART are fat redistribution, elevated triglycerides, and potential insulin resistance ( Louie et al. 2002, Highleyman 2000). These side effects may increase cardiovascular morbidity, and thus the mortality rate among AIDS patients may rise in the future even with successful therapy. However, mortality from non AIDS or immunological difficulties would not be considered relevant to a mortality rate due to infection by Cryptosporidium.

New Therapies New therapies for persons with AIDS may be developed sometime before 2028 ( the extent of the period of analysis in this EA). Therapies that extend life would create a new statistical time shift, as described at the beginning of R. 4. These therapies could be more effective than current ones against drug resistant strains, could be more easily tolerated, or could provide benefits longer than current therapies. Extensive research is being conducted on HIV vaccines and therapies, which include integrase inhibitors, fusion inhibitors, gene therapies, and pseudovirion and other vaccines. The likelihood of new therapies being developed and the possible time line for their use is difficult to foresee.

R. 5 Sensitivity Analysis This section presents the impact of using alternative estimates for the AIDS mortality adjustment factor. This is done in two ways. The first way is to discuss the differences of using the newer estimates now available from the CDC. The second is a more generic sensitivity analysis that will examine the impact on the benefits estimates of using factors above and below the estimates used in the EA analysis. The changes in AIDS mortality rates do not produce a one to one change in estimates in benefits because other factors ( such as the populations served by filtered and unfiltered systems, the mortality rate for the general population, income growth and income elasticity, and the cost of illness) also contribute to the estimate of benefits.

R. 5.1 Impacts of Using Recent CDC Estimates The results of using alternative values derived from more recent CDC estimates of deaths and persons living with AIDS to estimate total benefits are shown in Exhibit R. 4. Economic Analysis for the LT2ESWTR Proposal R 8 June 2003 Exhibit R. 4 Percent Changes in Estimated Total Benefits Using Recent CDC Estimates for AIDS Related Deaths and Persons Living With AIDS Lower Confidence Bound Mean Upper Confidence Bound Benefits Estimated Using Revised 1999 Data Percent Change in AIDS Mortality Factor from EA + 50% + 50% + 50%

Percent Change in Benefits from EA + 6% + 19% + 27%

Benefits Estimated Using Initial 2000 Data Percent Change in AIDS Mortality Factor from EA  14%  14%  14%

Percent Change in Benefits from EA  5%  8%  11%

Source: Risk Assessment Model. Note: Percentages are correct for both 3 and 7 percent discount rates.

These differences are not significant enough to reverse the general conclusion of benefits exceeding costs. Benefits so greatly exceed costs   by factors of 3 to 13 fold ( Exhibits 8.6a and 8.6b)   that benefit estimates 8 percent lower ( the mean percent change using 2000 data) would not alter that conclusion.

These differences also do not significantly change the relative rankings of the alternatives, or the choice of the Preferred Alternative. Appendix P addressed this question by looking at alternative values for the cost of illness. Comparing the results of Exhibit R. 4 to those in Exhibits P. 14 and P. 15 is helpful. Exhibits P. 14 and P. 15 display the effect of using a benefit estimate that is 22 percent higher and an estimate that is 18 percent lower than used in the EA. Using the Revised 1999 estimate would result in a 19 percent increase in the mean estimate of benefits, comparable to the 22 percent values used in Exhibits P. 14 and P. 15. Using the initial 2000 data would result in a decrease of 8 percent ( at the mean), about a half of the decrease shown in Exhibits P. 14 and P. 15. One conclusion is that using the revised 1999 data ( the values higher than in the EA), the Preferred Alternative is and remains the alternative with the highest net benefits in three of the four conditions of discount rates and underlying data sets, and becomes the alternative with the highest net benefits in the fourth. Using the 2000 data for AIDS mortality, the Preferred Alternative is and remains the alternative with the highest net benefits in three of the four conditions, and is and remains a close second best in the fourth ( ICRSSL, 7 percent). In summary, the Preferred Alternative would not lose its relative advantage using these alternative estimates for AIDSrelated mortality.

R. 5.2 Impacts of Using Alternative Estimates for AIDS Related Mortality The discussion in section R. 4 of the factors that may affect AIDS related mortality in the future does not lead to a single conclusion. It suggests that there exist factors that could easily raise the mortality rate substantially higher than the rates seen in 1999 and projected for 2000, but new treatment breakthroughs could substantially lower the rate in future years. Benefits from the LT2ESWTR are projected to begin in 2008 and the analysis makes projections through 2028. Considering the length of the Economic Analysis for the LT2ESWTR Proposal R 9 June 2003 period of analysis and the lack of projections available regarding mortality rates, this section uses both higher and lower values to assess the possible impact of alternative AIDS mortality rates.

Whatever does happen to these rates in the future, it is unlikely that they will remain constant from 1999 or 2000 through 2028. For the purposes of this analysis, however, two stable " no trend" values are used. The first is double the rate used in the EA; the second is half of that used in the EA. These differences are larger than those considered in section R. 5.1, and have correspondingly greater impact on the estimate of total benefits ( Exhibit R. 5).

Exhibit R. 5. Percent Change in Estimated Total Benefits Using Double and Half the AIDS Related Mortality Rate Lower Confidence Bound Mean Upper Confidence Bound Percent Change in Total Benefits Using Double the AIDS Related Mortality Rate  18% + 41% + 53%

Percent Change in Total Benefits Using Half the AIDS Related Mortality Rate  21%  24%  25%

Source: Risk Assessment Model. Note: Percentages are correct for both 3 and 7 percent discount rates.

These impacts on the level of total benefits are, however, not significant enough to reverse the general conclusion of benefits exceeding costs. Benefits so greatly exceed costs   by factors of 4 to 13 fold ( Exhibit 8.5)   that benefit estimates 24 percent lower ( the mean percent at half the current value) would not alter that conclusion.

Further, these larger differences do not significantly change the relative rankings of the alternatives or the choice of the Preferred Alternative. Again, comparing the results of Exhibit R. 5 to those in Exhibits P. 14 and P. 15 is helpful. A 41 percent increase in benefits holds steady the Preferred Alternative's status as the alternative with the highest net benefits using the ICR data set. The Preferred Alternative goes from being top ranked to a close second to Alternative A2 in another ( ICRSSL, 3 percent). In the fourth set of conditions ( ICRSSL, 7 percent), the Preferred Alternative goes from being a close second ( to Alternative A4) to being the top ranked alternative. Thus, at such an increased level of AIDS related mortality ( and therefore benefits from avoided deaths), the choice of the Preferred Alternative remains reasonable considering the range of possible conditions.

In considering the low value for AIDS related mortality, it is near the line shown for Low Costof Illness in Exhibits P. 14 and P. 15 ( Low COI is  18 percent compared to  24 percent here). Using this lower value for AIDS mortality, the Preferred Alternative and Alternative A4 are nearly equal. With the ICRSSL data set, Alternative A4 would have higher net benefits ( with the Preferred Alternative a close second). Using the ICR data set ( 7 percent), Alternatives A4 and the Preferred Alternative are essentially equal, and using the ICR data set ( 3 percent), the Preferred Alternative has slightly higher net benefits. Using such a lower value alone for AIDS related mortality could challenge the selection of the Preferred Alternative. However, as noted earlier, the effect of this lower value would be offset Economic Analysis for the LT2ESWTR Proposal R 10 June 2003 somewhat by the consideration of greater unquantified benefits associated with the Preferred Alternative. In summary, given that increases in the AIDS mortality rate are deemed as likely as decreases, the conclusions of the EA and the selection of the Preferred Alternative are not challenged.

In conclusion, the projection of AIDS related mortality rate is uncertain. If the factors identified as exerting an upward influence on the AIDS related mortality rate continue, the decline observed in this rate over the past several years will soon bottom out, and AIDS related mortality will begin to increase. Less certain is the possibility or timing of new therapies that could lessen the threat from this disease, but substantial resources are devoted to this outcome. Mortality rates ranging from above to somewhat below current estimates support the selection of the Preferred Alternative. Mortality rates that are substantially lower would support careful consideration of other alternatives and perhaps more careful enumeration of other benefits not now quantified.

. Economic Analysis for the LT2ESWTR Proposal June 2003 S 1 Appendix S Analysis of Individual Risk by Initial Bin S. 1 Introduction Under each regulatory alternative, systems are assigned an initial " bin" based on source water monitoring. This appendix groups population based on these bins and analyzes the distribution of individual risk for each of these bins. The conclusions are presented in two ways:

° Tabular information on the percent of the population that face annual risks of illness within selected ranges ( Exhibit S. 1). Additional tables show the data in several different forms ( Exhibits S. 2 through S. 4).

° Cumulative distribution graphs that show the distribution of individual risk based on Pre LT2ESWTR conditions, the distribution based on the minimal compliance with the LT2ESWTR, and based on the projected actual compliance with the rule ( Exhibits S. 5 through S. 12). These graphs are similar to Exhibit 5.12, where the full distributions of risks are presented. The graphs in this appendix give additional insight as to the distribution of risks within each bin before and after the rule.

The remainder of the appendix includes the following additional documentation:

° A discussion and graph of the relationship among Modeled True, Measured, and Binning concentrations of Cryptosporidium that is useful for understanding the derivation of the tables and graphs in this appendix.

° A discussion of the steps involved in computing the data for this appendix, with accompanying graphs that show the step by step process for a sample data set and regulatory alternative. This and the previous sections also serve as a good illustrations of how rule alternatives reduce risk.

Key assumptions in the analysis are the following:

° Only community water systems ( CWS) that filter water are considered in this analysis.

° The " bins" used in this analysis are those in which systems are initially classified. An initial bin contains all those systems whose source water places them in a bin. This includes those who are able to receive credits to reflect their current treatment in place and, therefore, lower requirements for additional treatment. For example, systems in the 1 log bin have to install treatment of 0.0, 0.5, or 1.0 log. It also includes systems who are projected to install treatment, but who would choose treatments that achieve greater than that required by their bin requirement.

° Variability from drinking water ingestion is not included. Economic Analysis for the LT2ESWTR Proposal June 2003 S 2 ° Data are based on means and thus excludes uncertainty.

S. 2 Percent of Population Within Selected Ranges of Annual Individual Risk Exhibits S. 1 through S. 4 show the percent of populations facing risk levels in different forms, all based on initial bin classifications and are of CWS only. Although the underlying data are the same, they are presented in different formats to help easily answer question of different forms.

° Exhibit S. 1 shows the percent of populations facing annual individual risk within exclusive selected ranges. It divides the total population into five levels of risk and shows the percent of the population within each level. This table uses global percentages and, therefore, data add both across and up to totals. This table is useful to answer questions about the proportion of the total population, such as, " What portion of the population in " no action" bins are estimated to have risks between 10 3or and 10 4?" and " What percent of the population is in the 1.0 log bin for alternative A4?"

° Exhibit S. 2 shows the percent of the total population facing risks at and above four levels   from 10 5or greater to 10 2 or greater annual risk of illness. These are cumulative of the numbers in Exhibit S. 1 and are still in the form of global percentages. The individual cell data can be summed up to column totals, but columns are to be compared, not summed. This table is useful to answer questions that focus on individual risk levels that might be of interest, and to identify what percent of the population face risks greater than that level, such as, " What portion of the total population in " no action" bins are estimated to have risks above 10 3?"

° Exhibit S. 3 uses the data in Exhibit S. 2, but expresses individual cell data as a percentage of the total in its column. These local percentages add vertically. This table is useful to answer questions about the percent composition of alternatives , such as, " What portion of the population under alternative A3 facing risks of 10 3 or greater are in the ` no action' bin?" ( For example, Exhibit S. 2 tells us that 2.04 percent of the total population are in this group, and Exhibit S. 2 tells us that they represent 71.84 percent of all those facing risks of 10 3 or greater.)

° Exhibit S. 4 shows the percentage of the population within a bin that exceed a specified risk level. The data derive from Exhibit S. 2 ( the percent of all those who are in that bin exceeding a risk level) divided by the percentage of the total population in that bin ( the first three columns). The first three columns add to 100 percent, but the other data are to be read individually and do not sum in any direction. This table is useful to answer questions such as, " What portion of the population in " no action" bins are estimated to have annual individual risks above 10 3?" Economic Analysis for the LT2ESWTR Proposal June 2003 S 3 A1 A2 A3 A4 A1 A2 A3 A4 A1 A2 A3 A4 A1 A2 A3 A4 A1 A2 A3 A4 A1 A2 A3 A4 Total 93.86% 47.19% 42.10% 26.34% 5.14% 33.06% 32.88% 32.77% 0.91% 18.41% 21.73% 30.19% 0.09% 1.35% 3.26% 10.13% 0.00% 0.00% 0.04% 0.58% 100.00% 100.00% 100.00% 100.00%

0.0 log 18.94% 19.72% 19.82% 21.11% 26.24% 27.36% 9.23% 16.53% 19.07% 0.58% 2.14% 3.05% 0.00% 0.01% 0.03% 49.85% 64.64% 69.32%

0.5 log 4.57% 3.81% 6.68% 3.45% 7.55% 9.98% 0.67% 5.93% 0.00% 0.24% 19.47% 23.41%

1.0 log 18.56% 2.71% 3.94% 1.96% 4.50% 1.14% 1.06% 1.15% 0.03% 0.31% 28.09% 7.27% 1.5 log 19.78% 2.56% 1.00% 0.07% 0.00% 23.41%

2.0 log 93.86% 2.83% 5.14% 1.34% 0.91% 0.19% 0.09% 0.01% 0.00% 0.00% 100.00% 4.37% 2.5 log 3.89% 0.99% 2.72% 1.36% 0.62% 0.50% 0.04% 0.05% 0.00% 0.00% 7.27% 2.90%

A1 A2 A3 A4 A1 A2 A3 A4 A1 A2 A3 A4 A1 A2 A3 A4 A1 A2 A3 A4 A1 A2 A3 A4 Total 97.25% 25.34% 21.07% 9.59% 2.61% 33.10% 32.26% 32.64% 0.13% 36.50% 38.66% 44.78% 0.00% 5.05% 7.93% 12.75% 0.00% 0.01% 0.07% 0.23% 100.00% 100.00% 100.00% 100.00%

0.0 log 6.37% 6.82% 6.86% 23.77% 29.42% 30.43% 22.71% 35.08% 38.06% 2.87% 7.25% 8.93% 0.01% 0.06% 0.11% 55.72% 78.63% 84.38%

0.5 log 5.73% 2.48% 7.64% 2.10% 13.15% 6.65% 2.14% 3.78% 0.00% 0.12% 28.67% 15.12%

1.0 log 13.89% 0.25% 2.71% 0.12% 3.57% 0.08% 0.69% 0.05% 0.01% 0.01% 20.87% 0.50% 1.5 log 12.89% 1.56% 0.63% 0.04% 0.00% 15.12%

2.0 log 97.25% 0.33% 2.61% 0.11% 0.13% 0.02% 0.00% 0.00% 0.00% 0.00% 100.00% 0.46% 2.5 log 0.36% 0.03% 0.13% 0.02% 0.01% 0.00% 0.00% 0.00% 0.00% 0.00% 0.50% 0.05%

A1 A2 A3 A4 A1 A2 A3 A4 A1 A2 A3 A4 A1 A2 A3 A4 A1 A2 A3 A4 A1 A2 A3 A4 Total 95.60% 30.98% 26.27% 13.10% 4.01% 32.64% 32.00% 31.55% 0.38% 31.64% 33.87% 40.31% 0.01% 4.72% 7.76% 14.48% 0.00% 0.01% 0.10% 0.56% 100.00% 100.00% 100.00% 100.00%

0.0 log 9.02% 9.39% 9.43% 23.35% 27.91% 28.73% 19.09% 29.51% 32.23% 2.37% 6.46% 8.22% 0.01% 0.07% 0.14% 53.85% 73.34% 78.75%

0.5 log 5.00% 3.00% 6.18% 2.35% 11.48% 7.86% 2.25% 6.01% 0.01% 0.37% 24.90% 19.58% 1.0 log 15.96% 0.67% 3.45% 0.46% 4.26% 0.22% 1.30% 0.26% 0.03% 0.06% 24.99% 1.67%

1.5 log 16.02% 2.47% 0.99% 0.11% 0.00% 19.58%

2.0 log 95.60% 0.80% 4.01% 0.48% 0.38% 0.07% 0.01% 0.01% 0.00% 0.00% 100.00% 1.36% 2.5 log 0.94% 0.12% 0.64% 0.15% 0.09% 0.03% 0.00% 0.00% 0.00% 0.00% 1.67% 0.31% 1.00E 02 or greater Total 1.00E 02 or greater Total 1.00E 05 to 1.00E 04 1.00E 04 to 1.00E 03 1.00E 03 to 1.00E 02 1.00E 02 or greater Total 1.00E 04 to 1.00E 03 1.00E 03 to 1.00E 02 1.00E 03 to 1.00E 02 Initial Bin Initial Bin 1.00E 05 or Lower 1.00E 05 to 1.00E 04 Initial Bin 1.00E 05 or Lower 1.00E 05 to 1.00E 04 1.00E 04 to 1.00E 03 1.00E 05 or Lower ICR ICRSSM ICRSSL Exhibit S. 1 Percent of Total Population Within Levels of Individual Annual Risk of Illness for Filtered Systems, by Data Set, by Risk Level, by Alternative, by Initial Bin Economic Analysis for the LT2ESWTR Proposal June 2003 S 4 A1 A2 A3 A4 A1 A2 A3 A4 A1 A2 A3 A4 A1 A2 A3 A4 Total 6.15% 52.82% 57.90% 73.66% 1.00% 19.76% 25.02% 40.90% 0.09% 1.35% 3.30% 10.70% 0.00% 0.00% 0.04% 0.58%

0.0 log 30.92% 44.92% 49.50% 9.81% 18.69% 22.14% 0.58% 2.16% 3.07% 0.00% 0.01% 0.03%

0.5 log 14.90% 19.60% 8.22% 16.16% 0.67% 6.17% 0.00% 0.24%

1.0 log 9.53% 4.56% 5.59% 2.60% 1.09% 1.46% 0.03% 0.31%

1.5 log 3.63% 1.07% 0.07% 0.00%

2.0 log 6.15% 1.54% 1.00% 0.20% 0.09% 0.01% 0.00% 0.00%

2.5 log 3.38% 1.91% 0.66% 0.55% 0.04% 0.05% 0.00% 0.00%

A1 A2 A3 A4 A1 A2 A3 A4 A1 A2 A3 A4 A1 A2 A3 A4 Total 2.75% 74.66% 78.93% 90.41% 0.13% 41.56% 46.67% 57.77% 0.00% 5.06% 8.01% 12.99% 0.00% 0.01% 0.07% 0.23%

0.0 log 49.35% 71.80% 77.52% 25.58% 42.39% 47.09% 2.88% 7.31% 9.04% 0.01% 0.06% 0.11%

0.5 log 22.93% 12.63% 15.29% 10.54% 2.14% 3.89% 0.00% 0.12% 1.0 log 6.98% 0.26% 4.27% 0.14% 0.70% 0.06% 0.01% 0.01%

1.5 log 2.23% 0.68% 0.04% 0.00%

2.0 log 2.75% 0.13% 0.13% 0.02% 0.00% 0.00% 0.00% 0.00%

2.5 log 0.15% 0.02% 0.01% 0.00% 0.00% 0.00% 0.00% 0.00%

A1 A2 A3 A4 A1 A2 A3 A4 A1 A2 A3 A4 A1 A2 A3 A4 Total 4.40% 69.02% 73.73% 86.90% 0.39% 36.38% 41.73% 55.36% 0.01% 4.74% 7.86% 15.05% 0.00% 0.01% 0.10% 0.56%

0.0 log 44.82% 63.95% 69.32% 21.47% 36.03% 40.59% 2.38% 6.53% 8.35% 0.01% 0.07% 0.14%

0.5 log 19.90% 16.59% 13.73% 14.24% 2.25% 6.38% 0.01% 0.37%

1.0 log 9.04% 1.00% 5.58% 0.53% 1.33% 0.31% 0.03% 0.06%

1.5 log 3.56% 1.10% 0.11% 0.00%

2.0 log 4.40% 0.56% 0.39% 0.08% 0.01% 0.01% 0.00% 0.00%

2.5 log 0.73% 0.19% 0.09% 0.03% 0.00% 0.00% 0.00% 0.00% 1.00E 04 or greater Initial Bin Initial Bin 1.00E 05 or greater 1.00E 04 or greater 1.00E 02 or greater 1.00E 05 or greater Initial Bin 1.00E 03 or greater 1.00E 03 or greater 1.00E 02 or greater 1.00E 05 or greater 1.00E 04 or greater 1.00E 03 or greater 1.00E 02 or greater ICR ICRSSM ICRSSL Exhibit S. 2 Percent of Total Population Exceeding Levels of Individual Annual Risk for Filtered Systems, by Data Set, by Risk Level, by Alternative, by Initial Bin Economic Analysis for the LT2ESWTR Proposal June 2003 S 5 A1 A2 A3 A4 A1 A2 A3 A4 A1 A2 A3 A4 A1 A2 A3 A4 Total 100.00% 100.00% 100.00% 100.00% 100.00% 100.00% 100.00% 100.00% 100.00% 100.00% 100.00% 100.00% 100.00%  100.00% 100.00%

0.0 log 58.53% 77.58% 67.20% 49.65% 74.68% 54.15% 42.77% 65.42% 28.71%  33.33% 4.33%

0.5 log 28.20% 26.61% 41.61% 39.50% 49.44% 57.67%  42.29%

1.0 log 16.46% 6.19% 22.34% 6.35% 33.00% 13.62% 66.67% 53.38%

1.5 log 6.87% 5.40% 4.89%

2.0 log 100.00% 2.66% 100.00% 0.80% 100.00% 0.21% 100.00% 0.00%

2.5 log 6.40% 3.29% 3.34% 2.18% 2.89% 1.36%  0.00%

A1 A2 A3 A4 A1 A2 A3 A4 A1 A2 A3 A4 A1 A2 A3 A4 Total 100.00% 100.00% 100.00% 100.00% 100.00% 100.00% 100.00% 100.00% 100.00% 100.00% 100.00% 100.00%  100.00% 100.00% 100.00%

0.0 log 66.10% 90.97% 85.74% 61.56% 90.83% 81.53% 56.82% 91.32% 69.57% 62.50% 87.67% 46.98%

0.5 log 30.72% 13.97% 36.79% 18.24% 42.37% 29.96% 25.00% 49.57%

1.0 log 8.84% 0.28% 9.14% 0.24% 8.68% 0.46% 12.33% 3.45%

1.5 log 2.99% 1.62% 0.81% 12.50%

2.0 log 100.00% 0.16% 100.00% 0.03% 100.00% 0.00%  0.00%

2.5 log 0.19% 0.03% 0.03% 0.00% 0.00% 0.00% 0.00% 0.00%

A1 A2 A3 A4 A1 A2 A3 A4 A1 A2 A3 A4 A1 A2 A3 A4 Total 100.00% 100.00% 100.00% 100.00% 100.00% 100.00% 100.00% 100.00% 100.00% 100.00% 100.00% 100.00%  100.00% 100.00% 100.00%

0.0 log 64.95% 86.73% 79.77% 59.02% 86.35% 73.32% 50.21% 83.03% 55.51% 64.29% 67.35% 24.11%

0.5 log 28.83% 19.09% 37.73% 25.72% 47.51% 42.40% 35.71% 65.78%

1.0 log 12.26% 1.14% 13.38% 0.96% 16.90% 2.09% 32.65% 10.11%

1.5 log 5.16% 3.01% 2.26% 0.00%

2.0 log 100.00% 0.76% 100.00% 0.19% 100.00% 0.08%  0.00%

2.5 log 1.06% 0.25% 0.24% 0.08% 0.02% 0.00% 0.00% 0.00% ICR ICRSSM ICRSSL 1.00E 02 or greater 1.00E 02 or greater Initial Bin 1.00E 05 or greater 1.00E 04 or greater Initial Bin 1.00E 05 or greater 1.00E 04 or greater 1.00E 03 or greater Initial Bin 1.00E 05 or greater 1.00E 04 or greater 1.00E 03 or greater 1.00E 02 or greater 1.00E 03 or greater Exhibit S. 3 Initial Bin Distribution of Population Within an Alternative for Filtered Systems, by Data Set, by Risk Level Economic Analysis for the LT2ESWTR Proposal June 2003 S 6 A1 A2 A3 A4 A1 A2 A3 A4 A1 A2 A3 A4 A1 A2 A3 A4 A1 A2 A3 A4 Total 100.00% 100.00% 100.00% 100.00%

0.0 log 49.85% 64.64% 69.32% 62.01% 69.50% 71.41% 19.68% 28.91% 31.94% 1.16% 3.34% 4.43% 0.00% 0.02% 0.04%

0.5 log 19.47% 23.41% 76.51% 83.74% 42.22% 69.01% 3.43% 26.37% 0.00% 1.04% 1.0 log 28.09% 7.27% 33.93% 62.68% 19.90% 35.71% 3.87% 20.06% 0.09% 4.24%

1.5 log 23.41% 15.49% 4.55% 0.28% 0.00%

2.0 log 100.00% 4.37% 6.15% 35.28% 1.00% 4.60% 0.09% 0.16% 0.00% 0.00% 2.5 log 7.27% 2.90% 46.47% 65.80% 9.08% 18.81% 0.54% 1.55% 0.00% 0.00%

A1 A2 A3 A4 A1 A2 A3 A4 A1 A2 A3 A4 A1 A2 A3 A4 A1 A2 A3 A4 Total 100.00% 100.00% 100.00% 100.00%

0.0 log 55.72% 78.63% 84.38% 88.57% 91.32% 91.87% 45.91% 53.91% 55.81% 5.16% 9.30% 10.71% 0.01% 0.08% 0.13%

0.5 log 28.67% 15.12% 80.00% 83.57% 53.34% 69.70% 7.48% 25.74% 0.01% 0.76% 1.0 log 20.87% 0.50% 33.44% 50.79% 20.44% 26.98% 3.33% 11.90% 0.04% 1.59%

1.5 log 15.12% 14.76% 4.47% 0.27% 0.01%

2.0 log 100.00% 0.46% 2.75% 27.47% 0.13% 3.30% 0.00% 0.00% 0.00% 0.00% 2.5 log 0.50% 0.05% 28.77% 48.98% 2.38% 0.00% 0.00% 0.00% 0.00% 0.00%

A1 A2 A3 A4 A1 A2 A3 A4 A1 A2 A3 A4 A1 A2 A3 A4 A1 A2 A3 A4 Total 100.00% 100.00% 100.00% 100.00%

0.0 log 53.85% 73.34% 78.75% 83.24% 87.19% 88.03% 39.87% 49.13% 51.54% 4.42% 8.90% 10.61% 0.02% 0.09% 0.17%

0.5 log 24.90% 19.58% 79.92% 84.70% 55.12% 72.71% 9.04% 32.58% 0.02% 1.89% 1.0 log 24.99% 1.67% 36.16% 59.62% 22.34% 31.88% 5.31% 18.81% 0.13% 3.42%

1.5 log 19.58% 18.19% 5.60% 0.55% 0.00%

2.0 log 100.00% 1.36% 4.40% 41.25% 0.39% 5.74% 0.01% 0.44% 0.00% 0.00% 2.5 log 1.67% 0.31% 43.68% 60.84% 5.21% 11.00% 0.06% 0.00% 0.00% 0.00% 1.00E 02 or greater Initial Bin ICRSSM Bin Percent of Total Population Percent of Bin Population Exceeding Risk Level 1.00E 05 or greater 1.00E 04 or greater 1.00E 03 or greater 1.00E 02 or greater 1.00E 05 or greater 1.00E 04 or greater 1.00E 03 or greater 1.00E 02 or greater ICRSSL Bin Percent of Total Population Percent of Bin Population Exceeding Risk Level Initial Bin Initial Bin ICR Bin Percent of Total Population Percent of Bin Population Exceeding Risk Level 1.00E 05 or greater 1.00E 04 or greater 1.00E 03 or greater Exhibit S. 4 Percent of Population Within a Bin Exceeding Levels of Individual Annual Risk for Filtered Systems, by Data Set, by Risk Level, by Alternative, by Initial Bin Economic Analysis for the LT2ESWTR Proposal June 2003 S 7 S. 3 Graphs of the Cumulative Distribution of Annual Individual Risk by Bin The graphs of the distributions of individual risk for people served by all filtered systems are shown in the Economic Analysis in Exhibit 5.12. The graphs below are analogous, but only include CWS systems. The axes have been switched so that the cumulative percent is shown on the X axis and the variability from drinking water ingestion has been removed. There are separate charts for each rule alternative and each of two data sets, the ICR and ICRSSL ( twelve graphs in all, Exhibits S. 5 through S. 16). On each graph, vertical dashed lines separate the initial bins. Within each bin, the following three distributions are shown:

  the distribution of risk based on finished water occurrence, Pre LT2 ( after considering treatment in place and the effects of credits)

  the distribution of risk based on the treatment required by that rule alternative and that bin ( again taking into account the credits earned by some systems)

  the distribution of risk actually achieved, reflecting that many systems are expected to achieve more treatment than the minimum required Note that within a bin, each distribution is sorted independently, and therefore, a particular system may appear at different points in each of the distributions. Also note that the distributions based on finished water occurrence overlap, that is, some individuals in a lower bin have a higher risk than some in higher bins. This is due to misclassification of systems during the sampling process and to the differences in treatment in place between systems.

The differences between the alternatives can be seen at particular risk levels. For example, from Exhibit S. 2, we see that at a risk of 1x10 4 risk level ( that is, a 1 in 1,000 chance of becoming ill in a year), Alternative A3 leaves 25.02 percent of the total population at or above this risk overall ( ICR data). Exhibit S. 2 also shows that of those 25.02 percent exposed to the 1x10 4 risk level, 18.69 percent are in the No Action bin and 5.59 percent are in the 1 log bin. Exhibit S. 7 shows the distribution of that 25.02, 18.69, and 5.59 percent. It is the portion of the distributions above the 10 4 line. Interestingly, there are not significantly higher spikes in higher bins because of the additional treatment used under Alternative A3. ( Note that adding in the variability from drinking water ingestion would slightly heighten any spikes, reflecting those that drink more than the average amount of water.)

For another example, Exhibit S. 8 and Exhibit S. 2 show that for Alternative A4, 40.9 percent of the population is over a 1x10 4 risk level and is mostly in the No Action ( 22 percent of the population) and 0.5 log bins ( 16 percent). Over 16 percent of the population faces risks of 1x10 4 or greater and is in the 0.5 log bin. A significant spike also exists in the 1 log bin. At the higher level of 1x10 2 risk level ( that is, a 1 in 100 annual chance of becoming ill), Alternative A3 has almost no population above this level, but Alternative A4 has about 0.6 percent facing these risks.