USEPA. 2000c. Integrated Risk Information System ( IRIS). Toxicological Review of Chlorine Dioxide and Chlorite. Washington, DC: U. S. EPA. EPA/ 635/ R 00/ 007.

USEPA. 2000d. Review of the EPA's Draft Chloroform Risk Assessment by a Subcommittee of the Science Advisory Board. Science Advisory Board, Washington, DC. EPA SAB EC

00 009.

USEPA. 2000e. Science Advisory Board Final Report. Prepared for Environmental Economics Advisory Committee. July 27, 2000. EPA SAB  EEAC  00  013.

USEPA. 2000f. Integrated Risk Information System ( IRIS). Toxicological Review of Chloral Hydrate. Washington DC: U. S. EPA. EPA/ 635/ R 00/ 006.

USEPA. 2000f. Information Collection Rule Auxiliary 1 Database, Version 5, EPA 815 C 00

002, April 2000.

USEPA. 2000g. Method 321.8. In Methods for the Determination of Organic and Inorganic Compounds in Drinking Water, Volume 1. ORD NERL, Cincinnati, OH. EPA 815 R

00 014. ( Method is available at http:// www. epa. gov/ nerlcwww/ ordmeth. htm.) 277 USEPA. 2000h. Method 300.1. In Methods for the Determination of Organic and Inorganic Compounds in Drinking Water, Volume 1. ORD NERL, Cincinnati, OH. EPA 815 R

00 014. ( Method is available at http:// www. epa. gov/ safewater/ methods/ sourcalt. html.)

USEPA. 2000i. Science Advisory Board Final Report. Prepared for Environmental Economics Advisory Committee. July 27, 2000. EPA SAB  EEAC  00  013.

USEPA. 2001a. Integrated Risk Information System ( IRIS). Toxicological Review of Chloroform. Washington, DC: U. S. EPA. EPA/ 635/ R 01/ 001.

USEPA. 2001b. Integrated Risk Information System ( IRIS). Toxicological Review of Bromate.

Washington, DC: U. S. EPA. EPA/ 635/ R 01/ 002.

USEPA. 2001c. Method 317.0. Determination of Inorganic Oxyhalide Disinfection By Products in Drinking Water Using Ion Chromatography with the Addition of a Postcolumn Reagent for Trace Bromate Analysis. Revision 2.0. EPA 815 B 01 001. ( Available at http:// www. epa. gov/ safewater/ methods/ sourcalt. html.)

USEPA. 2001cd. Arsenic Rule Benefits Analysis: an SAB Review. August 30, 2001.

EPA  SAB  EC  01  008.

USEPA. 2002. Method 326.0. Determination of Inorganic Oxyhalide Disinfection By Products in Drinking Water Using Ion Chromatography Incorporating the Addition of a Suppressor Acidified Postcolumn Reagent for Trace Bromate Analysis. Revision 1.0. EPA 815 R

03 007. ( Available at http:// www. epa. gov/ safewater/ methods/ sourcalt. html.)

USEPA. 2003a. National Primary Drinking Water Regulations: Stage 2 Disinfectants and Disinfection Byproducts Rule; National Primary and Secondary Drinking Water Regulations: Approval of Analytical Methods for Chemical Contaminants; Proposed Rule.

68 FR 49548, August 18, 2003.

USEPA. 2003b. Integrated Risk Information System ( IRIS). Toxicologcal Review for 278 Dichloroacetic Acid: Consensus Review Draft. EPA 635/ R 03/ 007.

http:// www. epa. gov/ iris/ subst/ 0654. htm USEPA. 2003c. Stage 2 Occurrence and Exposure Assessment for Disinfectants and Disinfection Byproducts ( D/ DBPs). EPA 68 C 99 206.

USEPA. 2003d. Technologies and Costs for Control of Microbial Pathogens and Disinfection Byproducts. Prepared by the Cadmus Group and Malcolm Pirnie.

USEPA. 2003e. Draft Significant Excursion Guidance Manual. Washington, DC. EPA 815  D  03  004.

USEPA. 2003f. Method 552.3. Determination of Haloacetic Acids and Dalapon in Drinking Water by Liquid liquid Extraction, Derivatization, and Gas Chromatography with Electron Capture Detection. Revision 1.0. EPA 815 B 03 002. ( Available at http:// www. epa. gov/ safewater/ methods/ sourcalt. html.)

USEPA. 2004. Guidelines Establishing Test Procedures for the Analysis of Pollutants Under the Clean Water Act; National Primary Drinking Water Regulations; and National Secondary Drinking Water Regulations; Analysis and Sampling Procedures; Proposed Rule. 696 FR 18166, April 6, 2004.

USEPA. 2005a. Economic Analysis for the Final Stage 2 DBPRDisinfectants and Disinfection Byproducts Rule. Washington, DC. EPA XXX X XX XXX815 R 05 010.

USEPA. 2005b. Drinking Water Criteria Document for Brominated Trihalomethanes.

Washington, DC. EPA ######### 822 R 05 011.

USEPA. 2005c. Drinking Water Criteria Document for Brominated HaloaAcetic Acids.

Washington, DC. EPA ######### 822 R 05 007.

USEPA. 2005d. Drinking Water Addendum to the Criteria Document for MCAAMonochloroacetic Acid. Washington, DC. EPA ######### 822 R 05 008. 279 USEPA. 2005e. Drinking Water Addendum to the Criteria Document for TCAATrichloroacetic Acid. Washington, DC. EPA ######### 822 R 05 010.

USEPA. 2005f. Stage 2 Occurrence Assessment for the Final Stage 2 Disinfectants and Disinfection Byproducts Rule. Washington, DC. EPA ######### 815 R 05 011.

USEPA. 2005g. Initial Distribution System Evaluation Guidance Manual. Washington, DC. EPA ### # ## ###.

USEPA. 2005h. Guidelines Establishing Test Procedures for the Analysis of Pollutants Under the Clean Water Act; National Primary Drinking Water Regulations; and National Secondary Drinking Water Regulations; Analysis and Sampling Procedures; Final Rule.

FR XX: XX: XXXXX XXXXX. ( Date).

USEPA. 2005i. Technologies and Costs for the Control of Microbial ContaminantsFinal Long Term 2 Enhanced Surface Water Treatment Rule and Final Stage 2 Disinfectants and Disinfection Byproducts Rule. Washington, DC. EPA #########.

USEPA. 2005j815 R 05 012.

USEPA. 2005h. Method 327.0. Determination of Chlorine Dioxide and Chlorite Ion in Drinking Water Using Lissamine Green B and Horseradish Peroxidase with Detection by Visible Spectrophotometry. Revision 1.1. EPA 815 R 05 008. ( Available at http:// www. epa. gov/ safewater/ methods/ sourcalt. html.)

USEPA. 2005i. Guidelines for carcinogen risk assessment. Office of Research and Development, Washington, DC. EPA/ 630/ P 03/ 001F. Available online at http:// cfpub. epa. gov/ ncea/.

USEPA. 2005kj. Supplemental guidance for assessing susceptibility from early life exposure to carcinogens. Office of Research and Development, Washington, DC.

EPA/ 630/ R 03/ 003F. Available online at http:// cfpub. epa. gov/ ncea/. 280 USEPA. 2005lk. Office ofDrinking Water Occurrence and Health Advisory Values Addendum forto the IRIS Toxicological Review of Dichloroacetic Acid. Washington, DC. EPA #########. 822 R 05 009.

USEPA. 2005l. Method 415.3. Determination of Total Organic Carbon and Specific UV Absorbance at 254 nm in Source Water and Drinking Water. Revision 1.1. EPA/ 600/ R

05/ 055. ( Available at http:// www. epa. gov/ nerlcwww/ ordmeth. htm.)

USEPA. 2005m. Unregulated Contaminant Monitoring Regulation ( UCMR) for Public Water Systems Revions; Proposed Rule. 70 FR 49094, August 22, 2005.

USEPA. 2005n. Information Collection Request for National Primary Drinking Water Regulations: Final Stage 2 Disinfectants and Disinfection Byproducts Rule. Washington,

DC. EPA 815 Z 05 002.

USEPA. 2006. Initial Distribution System Evaluation Guidance Manual for the Final Stage 2 Disinfectants and Disinfection Byproducts Rule. Washington, DC. EPA 815 B 06 002.

USFDA ( Food and Drug Administration). 1994. Sanitizing Solutions. 21 Code of Federal Regulation, Part 178.1010.

http:// ecfr. gpoaccess. gov/ cgi/ t/ text/ text idx? c= ecfr& tpl=% 2Findex. tpl Villanueva, C. M., M. Kogevinas and J. O. Grimalt. 2001. Drinking water chlorination and adverse health effects: a review of epidemiological studies. Medicina Clinica 117( 1):

27 35. [( Spanish]).

Villanueva, C. M., Fernandez, F., Malats, N., Grimalt, J. O., and Kogenvinas, M. 2003.

Metaanalysis of Studies on Individual Consumption of Chlorinated Drinking Water and Bladder Cancer. Journal of Epidemiology Community Health 57: 166 173.

Villanueva, C. M., K. P. Cantor, S. Cordier, J. J. K. Jaakkola, W. D. King, C. F. Lynch, S. Porru and M. Kogevinas. 2004. Disinfection byproducts and bladder cancer a pooled analysis. 281 Epidemiology. 15( 3): 357 367.

Vinceti, M., G. Fantuzzi, L. Monici, et al. 2004. A retrospective cohort study of trihalomethane exposure through drinking water and cancer mortality in northern Italy. Science of the Total Environment. 330( 1 3): 47 53.

Vineis, P. 2004. A self fulfilling prophecy: are we underestimating the role of the environment in gene  environment interaction research? International Journal of Epidemiology. 33: 945

946.

Waller, K., S. H. Swan, G. DeLorenze, B. Hopkins. 1998. Trihalomethanes in drinking water and spontaneous abortion. Epidemiology. 9( 2): 134 140.

Waller, K., S. H. Swan, G. C. Windham and L. Fenster. 2001. Influence of exposure assessment methods on risk estimates in an epidemiologic study of total trihalomethane exposure and spontaneous abortion. Journal of Exposure Analysis and Environmental Epidemiology.

11( 6): 522 531.

Weinberg, H. S., S. W. Krasner, S. D. Richardson and A. D. Thruston, Jr. 2002. The Occurrence of Disinfection By Products ( DBPs) of Health Concern in Drinking Water: Results of a Nationwide DBP Occurrence Study, U. S. Environmental Protection Agency, National Exposure Research Laboratory, Athens, GA. EPA/ 600/ R 02/ 068.

http:// www. epa. gov/ athens/ publications/ EPA600R02068. pdf.

WHO. 2000. World Health Organization, International Programme on Chemical Safety ( IPCS).

Environmental Health Criteria 216: Disinfectants and Disinfectant By products.

Windham, GC, Swan SH, Fenster L, Neutra RR. 1992. Tap or bottled water consumption and spontaneous abortion: a 1986 case control study in California. Epidemiology. 3: 113 9.

Windham GC, Waller K, Anderson M, Fenster L, Mendola P, and Swan S. 2003. Chlorination by products in drinking water and menstrual cycle function. Environ Health Perspect: 282 doi: 10.1289/ ehp. 5922. http:// ehpnet1. niehs. nih. gov/ docs/ 2003/ 5922/ abstract. html.

Wrensch, M., S. H. Swan, J. Lipscomb, D. M. Epstein, R. R. Neutra, and L. Fenster. 1992.

Spontaneous abortions and birth defects related to tap and bottled water use, San Jose,

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Wright, J. M., J. Schwartz and D. W. Dockery. 2003. Effect of trihalomethane exposure on fetal development. Occupational and Environmental Medicine. 60( 3): 173 180.

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Xu, X., T. M. Marino, J. D. Laskin and C. P. Weisel. 2002. Pericutaneous absorption of trihalomethanes, haloacetic acids, and haloketones. Toxicology and Applied Pharmacology. 184( 1): 19 26.

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Toxicology. 198( 2004): 249 254.

Zheng, M., S. Andrews, and J. Bolton. 1999. Impacts of medium pressure UV on THM and HAA formation in pre UV chlorinated drinking water. Proceedings, Water Quality Technology Conference of the American Water Works Association, Denver, CO. [ National Primary Drinking Water Regulations: Stage 2 Disinfectants and Disinfection Byproducts Rule, Page 264 of 314.]

283 List of Subjects 40 CFR Part 9 Reporting and recordkeeping requirements.

40 CFR Part 141 Environmental protection, Chemicals, Indians lands, Incorporation by reference,

Intergovernmental relations, Radiation protection, Reporting and recordkeeping requirements,

Water supply.

40 CFR Part 142 Environmental protection, Administrative practice and procedure, Chemicals,

Indianslands Radiation protection, Reporting and recordkeeping requirements, Water supply.

Dated:

________________________________________ Stephen L. Johnson, Administrator For the reasons set forth in the preamble, title 40 chapter I of the Code of Federal Regulations is amended as follows:

PART 9  OMB Approvals under the Paperwork Reduction Act 1. The authority citation for part 9 continues to read as follows:

Authority: 7 U. S. C. 135 et seq., 136 136y; 15 U. S. C. 2001, 2003, 2005, 2006, 2601 2671; 21 284 U. S. C. 331j, 346a, 348; 31 U. S. C. 9701; 33 U. S. C. 1251 et seq., 1311, 1313d, 1314, 1318, 1321, 1326,

1330, 1342, 1344, 1345 ( d) and ( e), 1361; Executive Order 11735, 38 FR 21243, 3 CFR, 1971 1975 Comp. p. 973; 42 U. S. C. 241, 242b, 243, 246, 300f, 300g, 300g 1, 300g 2, 300g 3, 300g 4, 300g 5,

300g 6, 300j 1, 300j 2, 300j 3, 300j 4, 300j 9, 1857 et seq., 6901 6992k, 7401 7671q, 7542, 9601 9657,

11023, 11048.

2. In § 9.1 the table is amended by addingas follows:

a. under the indicated heading and" National Primary Drinking Water Regulations Implementation" by adding entries in numerical order:

a. Entries § 141 for " § 141.600  141.605, 141.620  141.626, and 141.630,

b. By revising the entry § 142.14( a) to read as follows, and c. By adding a new entry § 142.16( m). 629".

b. under the heading " National Primary Drinking Water Regulations Implementation" by removing entries " § 142.14( a), 142.14( a)  ( d)( 3)" and adding entries in numerical order for " 142.14( a) ( 1)  ( 7),

142.14( a)( 8), 142.14( b)  ( d) and 142.16( m) " as follows:

§ 9.1 OMB approvals under the Paperwork Reduction Act.

* * * * *

40 CFR citation OMB control No.

* * * * * * * *

* *

National Primary Drinking Water Regulations * * * * * * * *

* *

141.600  141.605 2040 XXXX2040 0265 141.620  141.626 2040 XXXX2040 0265 285 141.629 2040 XXXX2040 0265 National Primary Drinking Water Regulations Implementation * * * *

* 1 4 2 . 1 4 ( a ) 2 0 4 0  0 2 2 9 ,

2 0 4 0  0 0 9 0 ,

2 0 4 0  L T 2 ' s #

2040 XXXX * * ** * * * * * * *

142.14( a)( 1)  ( 7) 142.14( a)( 8) 142.14 ( b)  ( d) 2040 0205 2040 0265 2040 0090 * * * * * * *

142.16( m) 2040 XXXX2040 0265 * * * * *

PART 141  National Primary Drinking Water Regulations 3. The authority citation for part 141 continues to read as follows:

Authority: 42 U. S. C. 300f, 300g 1, 300g 2, 300g 3, 300g 4, 300g 5, 300g 6, 300j 4, 300j 9, and 300j 11.

4. Section 141.2 is amended by adding, in alphabetical order, definitions for " Combined distribution system", " Consecutive system", " Dual sample sets", " Finished water", " GAC20", " Locational running annual average", and " Wholesale system" and modifyingrevising the definition of " GAC10" to read as follows:

§ 141.2 Definitions.

* * * * *

Combined distribution system is the interconnected distribution system consisting of the distribution systems of wholesale systems and of the consecutive systems that receive finished water. 286 * * * * *

Consecutive system is a public water system that receives some or all of its finished water from one or more wholesale systems. Delivery may be through a direct connection or through the distribution system of one or more consecutive systems.

* * * * *

Dual sample set is a set of two samples collected at the same time and same location, with one sample analyzed for TTHM and the other sample analyzed for HAA5. Dual sample sets are collected for the purposes of conducting an IDSE under subpart U of this part and determining compliance with the TTHM and HAA5 MCLs under subpart V of this part.

* * * * *

Finished water is water that is introduced into the distribution system of a public water system and is intended for distribution and consumption without further treatment, except as treatment necessary to maintain water quality in the distribution system ( e. g., booster disinfection, addition of corrosion control chemicals).

* * * * *

GAC10 means granular activated carbon filter beds with an empty bed contact time of 10 minutes based on average daily flow and a carbon reactivation frequency of every 180 days, except that the reactivation frequency for GAC10 used as a best available technology for compliance with subpart V MCLs under § 141.64( b)( 2) shall be 120 days.

GAC20 means granular activated carbon filter beds with an empty bed contact time of 20 minutes based on average daily flow and a carbon reactivation frequency of every 240 days.

* * * * *

Locational running annual average ( LRAA) is the average of sample analytical results for samples taken at a particular monitoring location during the previous four calendar quarters.

* * * * * 287 Wholesale system is a public water system that treats source water as necessary to produce finished water and then delivers some or all of that finished water to another public water system. Delivery may be through a direct connection or through the distribution system of one or more consecutive systems.

5. Section 141.12 is amended by deleting all text to read as follows:

§ 141.12 [ Reserved] removed and reserved.

6. Section 141.30 is amended by deleting all text to read as follows:

§ 141.30 [ Reserved] removed.

7. Section 141.32 is amended by deleting all text to read as follows:

§ 141.32 [ Reserved] removed and reserved.

8. Section 141.33 is amended by revising the first sentence of paragraph ( a) introductory text and adding paragraph ( f) to read as follows:

§ 141.33 Record maintenance.

* * * * *

( a) Records of microbiological analyses and turbidity analyses made pursuant to this part shall be kept for not less than 5 years. * * *

* * * * *

( f) Copies of monitoring plans developed pursuant to this part shall be kept for the same period of time as the records of analyses taken under the plan are required to be kept under paragraph ( a) or ofor three years after modification, whichever is longer this section, except as specified elsewhere in this part. 288 9. Section 141.53 is amended by removingrevising the table and adding in its place the following tableto read as follows:

§ 141.53 Maximum contaminant level goals for disinfection byproducts.

* * * * *

Disinfection byproduct MCLG ( mg/ L)

Bromodichloromethane Bromoform Bromate Chlorite Chloroform Dibromochloromethane Dichloroacetic acid Monochloroacetic acid Trichloroacetic acid zero zero zero 0.8 0.07 0.06 zero 0.07 0.02 10. Section 141.64 is revised to read as follows:

§ 141.64 Maximum contaminant levels for disinfection byproducts.

( a) Bromate and chlorite. The maximum contaminant levels ( MCLs) for bromate and chlorite are as follows:

Disinfection byproduct MCL ( mg/ L)

Bromate Chlorite 0.010 1.0 ( 1) Compliance dates for CWSs and NTNCWSs. Subpart H systems serving 10,000 or more persons 289 must comply with this paragraph ( a) beginning January 1, 2002. Subpart H systems serving fewer than 10,000 persons and systems using only ground water not under the direct influence of surface water must comply with this paragraph ( a) beginning January 1, 2004.

( 2) The Administrator, pursuant to section 1412 of the Act, hereby identifies the following as the best technology, treatment techniques, or other means available for achieving compliance with the maximum contaminant levels for bromate and chlorite identified in this paragraph ( a):

Disinfection byproduct Best available technology Bromate Chlorite Control of ozone treatment process to reduce production of bromate Control of treatment processes to reduce disinfectant demand and control of disinfection treatment processes to reduce disinfectant levels ( b) TTHM and HAA5.

( 1) Subpart L  RAA compliance. ( i) Compliance dates. Subpart H systems serving 10,000 or more persons must comply with this paragraph ( b)( 1) beginning January 1, 2002. Subpart H systems serving fewer than 10,000 persons and systems using only ground water not under the direct influence of surface water must comply with this paragraph ( b)( 1) beginning January 1, 2004. All systems must comply with these MCLs until the date specified for subpart V compliance in § 141.620( c).

Disinfection byproduct MCL ( mg/ L)

Total trihalomethanes ( TTHM) Haloacetic acids ( five) ( HAA5) 0.080 0.060 ( ii) The Administrator, pursuant to section 1412 of the Act, hereby identifies the following as the best technology, treatment techniques, or other means available for achieving compliance with the maximum contaminant levels for TTHM and HAA5 identified in this paragraph ( b)( 1):

Disinfection byproduct Best available technology Total trihalomethanes ( TTHM) and Haloacetic acids ( five) ( HAA5) Enhanced coagulation or enhanced softening or GAC10, with chlorine as the primary and residual disinfectant ( 2) Subpart V  LRAA compliance. ( i) Compliance dates. The subpart V MCLs for TTHM and HAA5 must be complied with as a locational running annual average at each monitoring location beginning the 290 date specified for subpart V compliance in § 141.620( c).

Disinfection byproduct MCL ( mg/ L)

Total trihalomethanes ( TTHM) Haloacetic acids ( five) ( HAA5) 0.080 0.060 ( ii) The Administrator, pursuant to section 1412 of the Act, hereby identifies the following as the best technology, treatment techniques, or other means available for achieving compliance with the maximum contaminant levels for TTHM and HAA5 identified in this paragraph ( b)( 2) for all systems that disinfect their source water:

Disinfection byproduct Best available technology Total trihalomethanes ( TTHM) and Haloacetic acids ( five) ( HAA5) Enhanced coagulation or enhanced softening, plus GAC10; or nanofiltration with a molecular weight cutoff # 1000 Daltons; or GAC20 ( iii) The Administrator, pursuant to section 1412 of the Act, hereby identifies the following as the best technology, treatment techniques, or other means available for achieving compliance with the maximum contaminant levels for TTHM and HAA5 identified in this paragraph ( b)( 2) for consecutive systems and applies only to the disinfected water that consecutive systems buy or otherwise receive:

Disinfection byproduct Best available technology Total trihalomethanes ( TTHM) and Haloacetic acids ( five) ( HAA5) Systems serving $ 10,000: Improved distribution system and storage tank management to reduce detentionresidence time, plus the use of chloramines for disinfectant residual maintenance Systems serving < 10,000: Improved distribution system and storage tank management to reduce detentionresidence time 11. Section 141.131 is amended as follows:

a. by revising paragraph ( a),

b. by revising paragraphs ( b)( 1) and ( b)( 2),

c. by revising the first sentencetable in paragraph ( a)( 1) and replacing paragraph ( b)( 2) to read as follows: c)( 1),

d. by revising paragraphs ( d)( 2), ( d)( 3), ( d)( 4)( i), and ( d)( 4)( ii), 291 e. by adding paragraph ( d)( 6).

§ 141.131 Analytical requirements.

( a) General. ( 1) Systems must use only the analytical methods specified in this section, or their equivalent as approved by EPA, to demonstrate compliance with the requirements of this subpart and with the requirements of subparts U and V. * * *

* * * * * of this part. These methods are effective for compliance monitoring February 16, 1999, unless a different effective date is specified in this section or by the State.

( 2) The following documents are incorporated by reference. The Director of the Federal Register approves this incorporation by reference in accordance with 5 U. S. C. 552( a) and 1 CFR part 51. Copies may be inspected at EPA's Drinking Water Docket, 1301 Constitution Avenue, NW., EPA West, Room B102,

Washington, DC 20460, or at the National Archives and Records Administration ( NARA). For information on the availability of this material at NARA, call 202 741 6030, or go to:

http:// www. archives. gov/ federal_ register/ code_ of_ federal_ regulations/ ibr_ locations. html. EPA Method 552.1 is in Methods for the Determination of Organic Compounds in Drinking Water Supplement II,

USEPA, August 1992, EPA/ 600/ R 92/ 129 ( available through National Information Technical Service ( NTIS), PB92 207703). EPA Methods 502.2, 524.2, 551.1, and 552.2 are in Methods for the Determination of Organic Compounds in Drinking Water Supplement III, USEPA, August 1995,

EPA/ 600/ R 95/ 131 ( available through NTIS, PB95 261616). EPA Method 300.0 is in Methods for the Determination of Inorganic Substances in Environmental Samples, USEPA, August 1993, EPA/ 600/ R

93/ 100 ( available through NTIS, PB94 121811). EPA Methods 300.1 and 321.8 are in Methods for the Determination of Organic and Inorganic Compounds in Drinking Water, Volume 1, USEPA, August 2000, EPA 815 R 00 014 ( available through NTIS, PB2000 106981). EPA Method 317.0, Revision 2.0,

" Determination of Inorganic Oxyhalide Disinfection By Products in Drinking Water Using Ion 292 Chromatography with the Addition of a Postcolumn Reagent for Trace Bromate Analysis," USEPA, July 2001, EPA 815 B 01 001, EPA Method 326.0, Revision 1.0, " Determination of Inorganic Oxyhalide Disinfection By Products in Drinking Water Using Ion Chromatography Incorporating the Addition of a Suppressor Acidified Postcolumn Reagent for Trace Bromate Analysis," USEPA, June 2002, EPA 815 R

03 007, EPA Method 327.0, Revision 1.1, " Determination of Chlorine Dioxide and Chlorite Ion in Drinking Water Using Lissamine Green B and Horseradish Peroxidase with Detection by Visible Spectrophotometry," USEPA, May 2005, EPA 815 R 05 008 and EPA Method 552.3, Revision 1.0,

" Determination of Haloacetic Acids and Dalapon in Drinking Water by Liquid liquid Microextraction,

Derivatization, and Gas Chromatography with Electron Capture Detection," USEPA, July 2003, EPA 815

B 03 002 can be accessed and downloaded directly on line at www. epa. gov/ safewater/ methods/ sourcalt. html. EPA Method 415.3, Revision 1.1, " Determination of Total Organic Carbon and Specific UV Absorbance at 254 nm in Source Water and Drinking Water,"

USEPA, February 2005, EPA/ 600/ R 05/ 055 can be accessed and downloaded directly on line at www. epa. gov/ nerlcwww/ ordmeth. htm. Standard Methods 4500 Cl D, 4500 Cl E, 4500 Cl F, 4500 Cl G,

4500 Cl H, 4500 Cl I, 4500 ClO2 D, 4500 ClO2 E, 6251 B, and 5910 B shall be followed in accordance with Standard Methods for the Examination of Water and Wastewater, 19thor 20th Editions, American Public Health Association, 1995 and 1998, respectively. The cited methods published in either edition may be used. Standard Methods 5310 B, 5310 C, and 5310 D shall be followed in accordance with the Supplement to the 19th Edition of Standard Methods for the Examination of Water and Wastewater, or the Standard Methods for the Examination of Water and Wastewater, 20th Edition, American Public Health Association, 1996 and 1998, respectively. The cited methods published in either edition may be used.

Copies may be obtained from the American Public Health Association, 1015 Fifteenth Street, NW,

Washington, DC 20005. Standard Methods 4500 Cl D 00, 4500 Cl E 00, 4500 Cl F 00, 4500 Cl G 00,

4500 Cl H 00, 4500 Cl I 00, 4500 ClO2 E 00, 6251 B 94, 5310 B 00, 5310 C 00, 5310 D 00 and 5910 B 00 are available at http:// www. standardmethods. org or at EPA's Water Docket. The year in which each 293 method was approved by the Standard Methods Committee is designated by the last two digits in the method number. The methods listed are the only Online versions that are IBR approved. ASTM Methods D 1253 86 and D 1253 86 ( Reapproved 1996) shall be followed in accordance with the Annual Book of ASTM Standards, Volume 11.01, American Society for Testing and Materials International, 1996 or any ASTM edition containing the IBR approved version of the method may be used. ASTM Method D1253

03 shall be followed in accordance with the Annual Book of ASTM Standards, Volume 11.01, American Society for Testing and Materials International, 2004 or any ASTM edition containing the IBR approved version of the method may be used. ASTM Method D 6581 00 shall be followed in accordance with the Annual Book of ASTM Standards, Volume 11.01, American Society for Testing and Materials International, 2001 or any ASTM edition containing the IBR approved version of the method may be used;

copies may be obtained from the American Society for Testing and Materials International, 100 Barr Harbor Drive, West Conshohocken, PA 19428 2959.

( b) Disinfection byproducts. ( 1) * * *

Systems must measure disinfection byproducts by the methods ( as modified by the footnotes) listed in the following table: 294 APPROVED METHODS FOR DISINFECTION BYPRODUCT COMPLIANCE MONITORING Contaminant and methodology1 EPA Method Standard Method2 SM Online9 ASTM Method3 TTHM P& T/ GC/ ElCD & PID 502.24 P& T/ GC/ MS 524.2 LLE/ GC/ ECD 551.1 HAA5 LLE ( diazomethane)/ GC/ ECD .................... 6251 B5 6251 B 94 SPE ( acidic methanol)/ GC/ ECD 552.15 LLE ( acidic methanol)/ GC/ ECD 552.2, 552.3 Bromate Ion chromatography 300.1 .................... ................ D 6581 00 Ion chromatography & post column reaction 317.0 Rev 2.06, 326.06 IC/ ICP MS 321.86,7 Chlorite Amperometric titration ..................... 4500 ClO2 E8 4500 ClO2 E 008 ................

Spectrophotometry 327.0 Rev 1.18 .................... ................ ................

Ion chromatography 300.0, 300.1, 317.0 Rev 2.0, 326.0 .................... ................ D 6581 00 1P& T = purge and trap; GC = gas chromatography; ElCD = electrolytic conductivity detector; PID = photoionization detector; MS = mass spectrometer; LLE = liquid/ liquid extraction; ECD = electron capture detector; SPE = solid phase extraction; IC = ion chromatography; ICP MS = inductively coupled plasma/ mass spectrometer. 219th and 20th editions of Standard Methods for the Examination of Water and Wastewater, 1995 and 1998, respectively, American Public Health Association; either of these editions may be used. 3Annual Book of ASTM Standards, 2001 or any year containing the cited version of the method, Vol 11.01. 4If TTHMs are the only analytes being measured in the sample, then a PID is not required. 5The samples must be extracted within 14 days of sample collection. 6 Ion chromatography & post column reaction or IC/ ICP MS must be used for monitoring of bromate for purposes of demonstrating eligibility of reduced monitoring, as prescribed in § 141.132( b)( 3)( ii). 7Samples must be preserved at the time of sampling with 50 mg ethylenediamine ( EDA)/ L of sample and must be analyzed within 28 days. 8Amperometric titration or spectrophotometry may be used for routine daily monitoring of chlorite at the entrance to the distribution system, as prescribed in § 141.132( b)( 2)( i)( A). Ion chromatography must be used for routine monthly monitoring of chlorite and additional monitoring of chlorite in the distribution system, as prescribed in § 141.132( b)( 2)( i)( B) and ( b)( 2)( ii). 295 9The Standard Methods Online version that is approved is indicated by the last two digits in the method number which is the year of approval by the Standard Method Committee. Standard Methods Online are available at http:// www. standardmethods. org.

( 2) Analyses under this section for disinfection byproducts must be conducted by laboratories that have received certification by EPA or the State, except as specified under paragraph ( b)( 3) of this section. To receive certification to conduct analyses for the DBP contaminants in § § 141.64, 141.135, and subparts U and V of this part, the laboratory must:

( i) Analyze Performance Evaluation ( PE) samples that are acceptable to EPA or the State at least once during each consecutive 12 month period by each method for which the laboratory desires certification.

( ii) Until [ date one year after date of final rule publication] March 31, 2007, in these analyses of PE samples, the laboratory must achieve quantitative results within the acceptance limit on a minimum of 80%

of the analytes included in each PE sample. The acceptance limit is defined as the 95% confidence interval calculated around the mean of the PE study between a maximum and minimum acceptance limit of +/ 50%

and +/ 15% of the study mean.

( iii) Beginning [ date one year after date of final rule publication], April 1, 2007, the laboratory must achieve quantitative results on the PE sample analyses that are within the following acceptance limits:

DBP Acceptance Limits ( percent of true value) Comments TTHM Chloroform Bromodichloromethane Dibromochloromethane Bromoform ± 20 ± 20 ± 20 ± 20 Laboratory must meet all 4 individual THM acceptance limits in order to successfully pass a PE sample for TTHM HAA5 Monochloroacetic Acid Dichloroacetic Acid Trichloroacetic Acid Monobromoacetic Acid Dibromoacetic Acid ± 40 ± 40 ± 40 ± 40 ± 40 Laboratory must meet the acceptance limits for 4 out of 5 of the HAA5 compounds in order to successfully pass a PE sample for HAA5 Chlorite ± 30 Bromate ± 30 ( iv) Beginning [ date one year after date of final rule publication] April 1, 2007, report quantitative data for 296 concentrations at least as low as the ones listed in the following table for all DBP samples analyzed for compliance with § § 141.64, 141.135, and subparts U and V of this part:

DBP Minimum reporting level ( mg/ L) 1 Comments TTHM 2 Chloroform Bromodichloromethane Dibromochloromethane Bromoform 0.0010 0.0010 0.0010 0.0010 HAA5 2 Monochloroacetic Acid Dichloroacetic Acid Trichloroacetic Acid Monobromoacetic Acid Dibromoacetic Acid 0.0020 0.0010 0.0010 0.0010 0.0010 Chlorite 0.020 Applicable to monitoring as prescribed in § 141.132( b)( 2)( i1)( B) and ( b)( 2)( ii).

Bromate 0.0050 or 0.0010 Laboratories that use EPA Methods 317.0 Revision 2.0, 326.0 or 321.8 must meet a 0.0010 mg/ L MRL for bromate.

1 The calibration curve must encompass the regulatory minimum reporting level ( MRL) concentration. Data may be reported for concentrations lower than the regulatory MRL as long as the precision and accuracy criteria are met by analyzing an MRL check standard at the lowest reporting limit chosen by the laboratory. The laboratory must verify the accuracy of the calibration curve at the MRL concentration by analyzing an MRL check standard with a concentration less than or equal to 110% of the MRL with each batch of samples. The measured concentration for the MRL check standard must be ± 50% of the expected value, if any field sample in the batch has a concentration less than 5 times the regulatory MRL. Method requirements to analyze higher concentration check standards and meet tighter acceptance criteria for them must be met in addition to the MRL check standard requirement. 2 When adding the individual trihalomethane or haloacetic acid concentrations to calculate the TTHM or HAA5 concentrations, respectively, a zero is used for any analytical result that is less than the MRL concentration for that DBP, unless otherwise specified by the State.

( 3) * * *

* * * * *

* * * * *

( c) *** 297 ( 1) ***

Methodology SM ( 19th or 20th ed) SM Online2 ASTM method EPA method Residual Measured1 Free Cl2 Combined Cl2 Total Cl2 ClO2 Amperometric Titration 4500 Cl D 4500 Cl D 00 D 1253 86 ( 96), 03 X X X Low Level Amperometric Titration 4500 Cl E 4500 Cl E 00 X DPD Ferrous Titrimetric 4500 Cl F 4500 Cl F 00 X X X DPD Colorimetric 4500 Cl G 4500 Cl G 00 X X X Syringaldazine ( FACTS) 4500 Cl H 4500 Cl H 00 X Iodometric Electrode 4500 Cl I 4500 Cl I 00 X DPD 4500 ClO2 D X Amperometric Method II 4500 ClO2 E 4500 ClO2 E 00 X Lissamine Green Spectrophotometric 327.0 Rev 1.1 X 1 X indicates method is approved for measuring specified disinfectant residual. Free chlorine or total chlorine may be measured for demonstrating compliance with the chlorine MRDL and combined chlorine or total chlorine may be measured for demonstrating compliance with the chloramine MRDL. 2The Standard Methods Online version that is approved is indicated by the last two digits in the method number which is the year of approval by the Standard Method Committee. Standard Methods Online are available at http:// www. standardmethods. org.

* * * * *

( d) ***

( 2) Bromide. EPA Methods 300.0, 300.1, 317.0 Revision 2.0, 326.0, or ASTM D 6581 00.

( 3) Total Organic Carbon ( TOC). Standard Method 5310 B or 5310 B 00 ( High Temperature Combustion Method) or Standard Method 5310 C or 5310 C 00 ( Persulfate Ultraviolet or 298 Heated Persulfate Oxidation Method) or Standard Method 5310 D or 5310 D 00 ( Wet Oxidation Method)

or EPA Method 415.3 Revision 1.1. Inorganic carbon must be removed from the samples prior to analysis.

TOC samples may not be filtered prior to analysis. TOC samples must be acidified at the time of sample collection to achieve pH less than or equal to 2 with minimal addition of the acid specified in the method or by the instrument manufacturer. Acidified TOC samples must be analyzed within 28 days.

( 4) ***

( i) Dissolved Organic Carbon ( DOC). Standard Method 5310 B or 5310 B 00 ( High Temperature Combustion Method) or Standard Method 5310 C or 5310 C 00 ( Persulfate Ultraviolet or Heated Persulfate Oxidation Method) or Standard Method 5310 D or 5310 D 00 ( Wet Oxidation Method)

or EPA Method 415.3 Revision 1.1. DOC samples must be filtered through the 0.45 µ m pore diameter filter as soon as practical after sampling, not to exceed 48 hours. After filtration, DOC samples must be acidified to achieve pH less than or equal to 2 with minimal addition of the acid specified in the method or by the instrument manufacturer. Acidified DOC samples must be analyzed within 28 days of sample collection. Inorganic carbon must be removed from the samples prior to analysis. Water passed through the filter prior to filtration of the sample must serve as the filtered blank. This filtered blank must be analyzed using procedures identical to those used for analysis of the samples and must meet the following criteria: DOC < 0.5 mg/ L.

( ii) Ultraviolet Absorption at 254 nm ( UV254). Standard Method 5910 B or 5910 B 00 ( Ultraviolet Absorption Method) or EPA Method 415.3 Revision 1.1. UV absorption must be measured at 253.7 nm ( may be rounded off to 254 nm). Prior to analysis, UV254 samples must be filtered through a 0.45 µ m pore diameter filter. The pH of UV254 samples may not be adjusted. Samples must be analyzed as soon as practical after sampling, not to exceed 48 hours.

* * * * *

( 6) Magnesium. All methods allowed in § 141.23( k)( 1) for measuring magnesium. 299 12. Section 141.132 is amended by:

a. redesignating paragraphs ( b)( 1)( iii) through ( b)( 1)( v) as paragraphs ( b)( 1)( iv) through ( b)( 1)( vi),

b. adding a new paragraph ( b)( 1)( iii), and ac. adding the following sentence as the first sentence to the currentnewly redesignated paragraph ( b)( 1)( iii),

b. redesignating paragraphs ( b)( 1)( iii) through ( b)( 1)( v) as paragraphs ( b)( 1)( iv) through ( b)( 1)( vi) and adding a new paragraph ( b)( 1)( iii), and c. removing paragraph ( b)( 3)( ii) and adding in its place the following paragraph:

iv) to read as follows:

§ 141.132 Monitoring requirements.

* * * * *

( b) * * *

( 1) * * *

( i) * * *

( ii) * * *

( iii) Monitoring requirements for source water TOC. In order to qualify for reduced monitoring for TTHM and HAA5 under paragraph ( b)( 1)( ii) of this section, subpart H systems not monitoring under the provisions of paragraph ( d) of this section must take monthly TOC samples every 30 days at a location prior to any treatment, beginning April 1, 2008 or earlier, if specified by the State. In addition to meeting other criteria for reduced monitoring in paragraph ( b)( 1)( ii) of this section, the source water TOC running annual average must be # 4.0 mg/ L ( based on the most recent four quarters of monitoring) on a continuing basis at each treatment plant to reduce or remain on reduced monitoring for TTHM and HAA5. Once qualified for reduced monitoring for TTHM and HAA5 under paragraph ( b)( 1)( ii) of this section, a system may reduce source water TOC monitoring to quarterly TOC samples taken every 90 days at a location 300 prior to any treatment.

( iv) Systems on a reduced monitoring schedule may remain on that reduced schedule as long as the average of all samples taken in the year ( for systems which must monitor quarterly) or the result of the sample ( for systems which must monitor no more than frequently than annually) is no more than 0.060 mg/ L and 0.045 mg/ L for TTHMs and HAA5, respectively. Systems that do not meet these levels must resume monitoring at the frequency identified in paragraph ( b)( 1)( i) of this section ( minimum monitoring frequency column) in the quarter immediately following the monitoring period in which the system exceeds 0.060 mg/ L or 0.045 mg/ L for TTHMs and HAA5, respectively. For systems using only ground water not under the direct influence of surface water and serving fewer than 10,000 persons, if either the TTHM annual average is > 0.080 mg/ L or the HAA5 annual average is > 0.060 mg/ L, the system must go to the increased monitoring identified in paragraph ( b)( 1)( i) of this section ( sample location column) in the quarter immediately following the monitoring period in which the system exceeds 0.80080 mg/ L or 0.060 mg/ L for TTHMs or HAA5 respectively.

( v) Systems on increased monitoring may return to routine monitoring if, after at least one year of monitoring their TTHM annual average is < 0.060 mg/ L and their HAA5 annual average is < 0.045mg/ L.

( vi) The State may return a system to routine monitoring at the State's discretion.

* * * * *

( 3) ***

( i) ***

( ii) Reduced monitoring.

( A) Until [ date three years from final rule publication] March 31, 2009, systems required to analyze for bromate may reduce monitoring from monthly to quarterly, if the system's average source water bromide concentration is less than 0.05 mg/ L based on representative monthly bromide measurements for one year.

The system may remain on reduced bromate monitoring until the running annual average source water bromide concentration, computed quarterly, is equal to or greater than 0.05 mg/ L based on representative 301 monthly measurements. If the running annual average source water bromide concentration is $ 0.05 mg/ L,

the system must resume routine monitoring required by paragraph ( b)( 3)( i) of this section in the following month.

( B) Beginning [ date three years from final rule publication] April 1, 2009, systems may no longer use the provisions of paragraph ( b)( 3)( ii)( A) of this section to qualify for reduced monitoring. A system required to analyze for bromate may reduce monitoring from monthly to quarterly, if the system's running annual average bromate concentration is # 0.0025 mg/ L based on monthly bromate measurements under paragraph ( b)( 3)( i) of this section for the most recent four quarters, with samples analyzed using Method 317.0 Revision 2.0, 326.0 or 321.8. If a system has qualified for reduced bromate monitoring under paragraph ( b)( 3)( ii)( A) of this section, that system may remain on reduced monitoring as long as the running annual average of quarterly bromate samples # 0.0025 mg/ L based on samples analyzed using Method 317.0 Revision 2.0, 326.0, or 321.8. If the running annual average bromate concentration is > 0.0025 mg/ L, the system must resume routine monitoring required by paragraph ( b)( 3)( i) of this section.

* * * * *

§ 141.133  [ AMENDED]

13. Section 141.133( d) is amended by revisingin the last sentence by replacing " § 141.32" and add in its place " subpart Q".

§ 141.135 [ AMENDED] of paragraph ( d) by revising the reference " § 141.32" to read " subpart Q of this part".

14. Section 141.135 is amended by revising paragraph ( a)( 3)( ii) by adding the phrase " according to § 141.131( d)( 6)" to read as follows: 302 § 141.135 Treatment technique for control of disinfection byproduct ( DBP) precursors.

( a) * * *

( 3) * * *

( ii) Softening that results in removing at least 10 mg/ L of magnesium hardness ( as CaCO3), measured monthly according to § 141.131( d)( 6) and calculated quarterly as a running annual average.

* * * * *

Subpart O  [ amended]

15. Section 141.151 is amended by revising paragraph ( d) to read as follows:

§ 141.151 Purpose and applicability of this subpart.

* * * * *

( d) For the purpose of this subpart, detected means: at or above the levels prescribed by § 141.23( a)( 4) for inorganic contaminants, at or above the levels prescribed by § 141.24( f)( 7) for the contaminants listed in § 141.61( a), at or above the levels prescribed by § 141.24( h)( 18) for the contaminants listed in § 141.61( c),

at or above the levels prescribed by § 141.131( b)( 2)( iv) for the contaminants or contaminant groups listed in § 141.64, and at or above the levels prescribed by § 141.25( c) for radioactive contaminants.

* * * * *

16. Section 141.153 is amended by removingrevising paragraphs ( d)( 4)( iv)( B) and ( d)( 4)( iv)( C) and adding two paragraphs in their place to read as follows:

§ 141.153 Content of the reports.

* * * * *

( d) * * *

( 4) * * *

( iv) * * * 303 ( A) * * *

( B) When compliance with the MCL is determined by calculating a running annual average of all samples taken at a monitoring location: the highest average of any of the monitoring locations and the range of all monitoring locations expressed in the same units as the MCL. For the MCLs for TTHM and HAA5 in § 141.64( b)( 2), systems must include the highest locational running annual average for TTHM and HAA5 and the range of individual sample results for all monitoring locations expressed in the same units as the MCL. If more than one location exceeds the TTHM or HAA5 MCL, the system must include the locational running annual averages for all locations that exceed the MCL.

( C) When compliance with the MCL is determined on a system wide basis by calculating a running annual average of all samples at all monitoring locations: the average and range of detection expressed in the same units as the MCL. The system is required to include the range of individual sample results for the IDSE conducted under subpart U asof this part ofwhen determining the range of TTHM and HAA5 results to be reported in the annual consumer confidence report for the calendar year that the IDSE samples were taken. ***

* * * * *

17. In Subpart Q, Appendix A is amended as follows:

a. a. In entry I. B. 2. in the fifth column, remove the endnote citation " 9" and add in its place " 11";

b. In entry I. B. 11. in the fourth column, remove the endnote citation " 10" and add in its place " 12";

c. In entry I. B. 12. in the fourth column, remove the endnote citation " 10" and add in its place " 12";

d. In entry I. G. in the first column, remove the endnote citation " 11" and add in its place " 13"; 304 e. In entry I. G. 1. in the third column, remove the endnote citation " 12" and add in its place " 14" and remove the citation in the third column " 141.12,141.64( a)" and in its place add " 141.64( b)" ( keeping the endnote citation to endnote 14) and in the fifth column remove the citation " 141.30" and add in numerical order the citations " 141.600 141.605, 141.620 141.629",

and;

b f. In entry I. G. 2. revise the entry " 141.64( a)" to read " 141.64( b)" and in the fifth column add in numerical order the citations " 141.600 141.605, 141.620 141.629".

g. In entry I. G. 7. in the fourth column, remove the endnote citation " 13" and add in its place " 15";

h. In entry I. G. 8. in the second column, remove the endnote citation " 14" and add in its place " 16";

i. In entry II. in the first column, remove the endnote citation " 15" and add in its place " 17";

j. In entry III. A. in the third column, remove the endnote citation " 16" and add in its place " 18";

k. In entry III. B in the third column, remove the endnote citation " 17" and add in its place " 19";

l. In entry IV. E. in the first column, remove the endnote citation " 18" and add in its place 20"; and m. In entry III. F in the second column, remove the endnote citation " 19" and add in its place " 21".

18. In Subpart Q, Appendix A, remove endnote14 and add in its place, to read as follows: " 14.

§ § 141.64( b)( 1) and 141.132( a)( b) apply until § § 141.620 141.630 take effect under the schedule 305 in § 141.620( c).

19. In Subpart Q, Appendix B is amended in entry H. 80, as follows:

a. In entry G. 77. in the third column, remove the endnote citation " 16" and add in its place " 17";

b. In entry H. ( the title) in the first column, remove the endnote citation " 17" and add in its place " 18";

c. In entry H. 80. in the third column, remove the endnote citations " 17, 18" and add in its place " 19, 20" and remove the number " 0.10/";

d. In entry H. 81. in the third column, remove the endnote citation " 20" and add in its place " 21"; and e. In entry H. 84. in the second column, remove the endnote citation " 21" and add in its place " 22" and in the third column by removingremove the number " 0.10/" endnote citation " 22"

and add in its place " 23".

20. In Subpart Q, Appendix B, remove endnotes 18 and 19 and add in their place, to read as follows: " 18.

Surface water systems and ground water systems under the direct influence of surface water are regulated under subpart H of 40 CFR 141. Subpart H community and non transient non community systems serving $ 10,000 must comply with subpart L DBP MCLs and disinfectant maximum residual disinfectant levels ( MRDLs) beginning January 1, 2002. All other community and non transient non community systems must comply with subpart L DBP MCLs and disinfectant MRDLs beginning January 1, 2004. Subpart H transient non community systems serving $ 10,000 that use chlorine dioxide as a disinfectant or oxidant must comply with the chlorine dioxide MRDL beginning January 1, 2002. All other transient noncommunity systems that use chlorine dioxide as a disinfectant or oxidant must comply with the chlorine 306 dioxide MRDL beginning January 1, 2004.

19. Community and non transient non community systems must comply with subpart V TTHM and HAA5 MCLs of 0.080 mg/ L and 0.060 mg/ L, respectively ( with compliance calculated as a locational running annual average) on the schedule in § 141.620."

21. Part 141 is amended by adding new subpart U to read as follows:

Subpart U Initial Distribution System Evaluations Sec.

141.600 General requirements.

141.601 Standard monitoring.

141.602 System specific studies.

141.603 40/ 30 certification.

141.604 Very small system waivers.

141.605 Subpart V monitoring location recommendations.

Subpart U Initial Distribution System Evaluations § 141.600 General requirements.

( a) The requirements of subpart U of this part constitute national primary drinking water regulations. The regulations in this subpart establish monitoring and other requirements for identifying subpart V compliance monitoring locations for determining compliance with maximum contaminant levels for total trihalomethanes ( TTHM) and haloacetic acids ( five)( HAA5). You willmust use an Initial Distribution System Evaluation ( IDSE) to determine locations with representative high TTHM and HAA5 concentrations throughout your distribution system. IDSEs are used in conjunction with, but separate from, subpart L compliance monitoring, to identify and select subpart V compliance monitoring locations.

( b) Applicability. You are subject to these requirements if your system is a community water system that uses a primary or residual disinfectant other than ultraviolet light or delivers water that has been treated 307 with a primary or residual disinfectant other than ultraviolet light; or if your system is a nontransient noncommunity water system that serves at least 10,000 people and uses a primary or residual disinfectant other than ultraviolet light or delivers water that has been treated with a primary or residual disinfectant other than ultraviolet light.

( c) Schedule. ( 1) You must comply with the requirements of this subpart on the schedule in the table in this paragraph ( c)( 1). 308 IF YOU SERVE THIS POPULATION YOU MUST SUBMIT YOUR STANDARD MONITORING PLAN/ SYSTEMPLAN OR SYSTEM SPECIFIC STUDY PLAN 1 OR 40/ 30 CERTIFICATION2 TO THE STATE BY OR RECEIVE VERY SMALL SYSTEM WAIVER FROM STATE YOU MUST COMPLETE YOUR STANDARD MONITORING OR SYSTEM SPECIFIC STUDY BY YOU MUST SUBMIT YOUR IDSE REPORT TO THE STATE BY 3 Systems that are not part of a combined distribution system and systems that serve the largest population in the combined distribution system ( i) $ 100,000 [ date six mos following publication of final rule][ date 30 mos following publication of final rule][ date 33 mos following publication of final rule] October 1, 2006 September 30, 2008 January 1, 2009 ( ii) 50,000

99,999 [ date 12 mos following publication of final rule][ date 36 mos following publication of final rule][ date 39 mos following publication of final rule] April 1, 2007 March 31, 2009 July 1, 2009 ( iii) 10,000

49,999 [ date 18 mos following publication of final rule][ date 42 mos following publication of final rule][ date 45 mos following publication of final rule] October 1, 2007 September 30, 2009 January 1, 2010 ( iv) < 10,000 ( CWS Only) [ date 24 mos following publication of final rule] [ date 48 mos following publication of final rule] [ date 51 mos following publication of final rule] April 1, 2008 March 31, 2010 July 1, 2010 Other systems that are part of a combined distribution system ( v) Wholesale system or consecutive  at the same time as the system with the earliest compliance date in the combined distribution system  at the same time as the system with the earliest compliance date in the combined distribution system  at the same time as the system with the earliest compliance date in the combined distribution system 309 1 If the State does not approve or modify your plan, within 12 months after the date identified in this column, the State does not approve your plan or notify you that it has not yet completed its review, you may consider the plan that you submitted as approved and. You must implement that plan so thatand you must complete standard monitoring or a system specific study no later than the date identified in the third column.

2 You must submit your 40/ 30 certification under § 141.603 by the date indicated. If you fail to submit your certification by the date indicated, even if you otherwise qualify for 40/ 30 certification, you must conduct either standard monitoring or a system specific study.

3 If the State does not approve or modify your IDSE report, within three months after the date identified in this column ( nine months after the date identified in this column if you must comply on the schedule in paragraph ( c)( 1)( iii) of this section), the State does not approve your IDSE report or notify you that it has not yet completed its review, you may consider the report that you submitted as approved and you must implement the recommended subpart V monitoring as required. 310 ( 2) For the purpose of the schedule in paragraph ( c)( 1) of this section, the State may determine that the combined distribution system does not include certain consecutive systems based on factors such as receiving water from a wholesale system only on an emergency basis or receiving only a small percentage and small volume of water from a wholesale system. The State may also determine that the combined distribution system does not include certain wholesale systems based on factors such as delivering water to a consecutive system only on an emergency basis or delivering only a small percentage and small volume of water to a consecutive system.

( d) You must conduct standard monitoring that meets the requirements in § 141.601, or a system specific study that meets the requirements in § 141.602, or certify to the State that you meet 40/ 30 certification criteria under § 141.603, or qualify for a very small system waiver under § 141.604.

( 1) You must have taken the full complement of routine TTHM and HAA5 compliance samples required of a system with your population and source water under subpart L of this part ( or you must have taken the full complement of reduced TTHM and HAA5 compliance samples required of a system with your population and source water under subpart L if you meet reduced monitoring criteria under subpart L of this part) during the two year period specified in § 141.603( a) to meet the 40/ 30 certification criteria in § 141.603. You must have taken TTHM and HAA5 samples under § § 141.131 and 141.132 to be eligible for the very small system waiver in § 141.604.

( 2) If you have not taken the required samples, you must conduct standard monitoring that meets the requirements in § 141.601, or a system specific study that meets the requirements in § 141.602.

( e) You must use only the analytical methods specified in § 141.131, or otherwise approved by EPA for monitoring under this subpart, to demonstrate compliance with the requirements of this subpart.

( f) IDSE results will not be used for the purpose of determining compliance with MCLs in § 141.64.

§ 141.601 Standard monitoring.

( a) Standard monitoring plan. Your standard monitoring plan must comply with paragraphs ( a)( 1) 311 through ( a)( 4) of this section. You must prepare and submit your standard monitoring plan to the State according to the schedule in § 141.600( c).

( 1) Your standard monitoring plan must include a schematic of your distribution system ( including distribution system entry points and their sources, and storage facilities), with notes indicating locations and dates of all projected standard monitoring, and all projected subpart L compliance monitoring noted.

( 2) Your standard monitoring plan must include justification of standard monitoring location selection and all additional summary of data you relied on to justify standard monitoring location selection.

( 3) Your standard monitoring plan must specify the population served and system type ( subpart H or ground water).

( 4) You must retain a complete copy of your standard monitoring plan submitted under this paragraph ( a),

including any State modification of your standard monitoring plan, for as long as you are required to retain your IDSE report under paragraph ( c)( 4) of this section.

( b) Standard monitoring. ( 1) You must monitor as indicated in the table in this paragraph ( b)( 1). You must collect dual sample sets at each monitoring location. One sample in the dual sample set must be analyzed for TTHM. The other sample in the dual sample set must be analyzed for HAA5. You must conduct one monitoring period during the peak historical month for TTHM levels or HAA5 levels or the month of warmest water temperature. You must review available compliance, study, or operational data to determine the peak historical month for TTHM or HAA5 levels or warmest water temperature. 312 Source Water Type Population Size Category Monitoring Periods and Frequency of Sampling Distribution System Monitoring Locations1 Total per monitoring period Near Entry Points Average Residence Time High TTHM Locations High HAA5 Locations Subpart H < 500 consecutive systems one ( during peak historical month) 2213 2 1 ! 1 !

< 500 nonconsecutive systems 2 ! ! 1 1 500 3,300 consecutive systems four ( every 90 days) 2 1 ! 1 !

500 3,300 nonconsecutive systems 2 ! ! 1 141 3,301 9,999 4 ! 1 2 1 10,000 49,999 six ( every 60 days) 8 1 2 3 2 50,000 249,999 16 3 4 5 4 250,000 999,999 24 4 6 8 6 1,000,000 4,999,999 32 6 8 10 8 $ 5,000,000 40 8 10 12 10 Ground Water < 500 consecutive systems one ( during peak historical month) 2 2 13 1 ! 1 !

< 500 nonconsecutive systems 2 ! ! 1 1 500 9,999 four ( every 90 days) 2 ! ! 1 141 10,000 99,999 6 1 1 2 2 100,000 499,999 8 1 1 3 3 $ 500,000 12 2 2 4 4 1 A dual sample set ( i. e., a TTHM and an HAA5 sample) must be taken at each monitoring location during each monitoring period. 2 The peak historical month is the month with the highest TTHM or HAA5 levels or the warmest water temperature. 3 You must monitor at or near the entry point if you are a consecutive system. If you are not a consecutive system, you must monitor at a high HAA5 location. 4 You must monitor at or near the entry point if you are a consecutive system.

( 2) You must take samples at locations other than the existing subpart L monitoring locations.

Monitoring locations must be distributed throughout the distribution system.

( 3) If the number of entry points to the distribution system is fewer than the specified number of entry 313 point monitoring locations, excess entry point samples must be replaced equally at high TTHM and HAA5 locations. If there is an odd extra location number, you must take a sample at a high TTHM location. If the number of entry points to the distribution system is more than the specified number of entry point monitoring locations, you must take samples at entry points to the distribution system having the highest annual water flows.

( 4) Your monitoring under this paragraph ( b) may not be reduced under the provisions of § 141.29 and the State may not reduce your monitoring using the provisions of § 142.16( m).

( c) IDSE report. Your IDSE report must include the elements required in paragraphs ( c)( 1) through ( c)( 4) of this section. You must submit your IDSE report to the State according to the schedule in § 141.600( c).

( 1) Your IDSE report must include all TTHM and HAA5 analytical results and LRAAs from subpart L compliance monitoring and all standard monitoring conducted during the period of the IDSE as individual analytical results and LRAAs presented in a tabular or spreadsheet format acceptable to the State. If changed from your standard monitoring plan submitted under paragraph ( a) of this section, your report must also include a schematic of your distribution system, the population served, and system type ( subpart H or ground water).

( 2) Your IDSE report must include an explanation of any deviations from your approved standard monitoring plan.

( 3) You must recommend and justify subpart V compliance monitoring locations and timing based on the protocol in § 141.605.

( 4) You must retain a complete copy of your IDSE report submitted under this section for 10 years after the date that you submitted your report. If the State modifies the subpart V monitoring requirements that you recommended in your IDSE report or if the State approves alternative monitoring locations, you must keep a copy of the State's notification on file for 10 years after the date of the State's notification. You must make the IDSE report and any State notification available for review by the State or the public. 314 § 141.602 System specific studies.

( a) System specific study plan. Your system specific study plan must be based on either existing monitoring results as required under paragraph ( a)( 1) of this section or modeling as required under paragraph ( a)( 2) of this section. You must prepare and submit your system specific study plan to the State according to the schedule in § 141.600( c).

( 1) Existing monitoring results. You may comply by submitting monitoring results collected before you are required to begin monitoring under § 141.600( c). The monitoring results and analysis must meet the criteria in paragraphs ( a)( 1)( i) and ( a)( 1)( ii) of this section.

( i) Minimum requirements. ( A) TTHM and HAA5 results must be based on samples collected and analyzed in accordance with § 141.131. Samples must be collected no earlier than five years prior to the study plan submission date.

( B) The monitoring locations and frequency must meet the conditions identified in this paragraph ( a)( 1)( i)( B). Each location must be sampled once during the month of highest TTHM or highestpeak historical month for TTHM levels or HAA5 levels or the month of warmest water temperature for every 12 months of data submitted for that location. Monitoring results must include all subpart L compliance monitoring results plus additional monitoring results as necessary to meet minimum sample requirements. 315 System Type Population Size Category Number of Monitoring Locations Number of Samples Subpart H TTHM HAA5 Surface Water < 500 3 3 3 500 3,300 3 9 9 3,301 9,999 6 36 36 10,000 49,999 12 72 72 50,000 249,999 24 144 144 250,000 999,999 36 216 216 1,000,000 4,999,999 48 288 288 $ 5,000,000 60 360 360 Ground Water < 500 3 3 3 500 9,999 3 9 9 10,000 99,999 12 48 48 100,000 499,999 18 72 72 $ 500,000 24 96 96 ( ii) Reporting monitoring results. You must report the information in this paragraph ( a)( 1)( ii).

( A) You must report previously collected monitoring results and certify that the reported monitoring results include all compliance and non compliance results generated during the time period beginning with the first reported result and ending with the most recent subpart L results.

( B) You must certify that the samples were representative of the entire distribution system and that treatment, and distribution system have not changed significantly since the samples were collected.

( C) Your system specific study monitoring plan must include a schematic of your distribution system ( including distribution system entry points and their sources, and storage facilities), with notes indicating 316 the locations and dates of all completed or planned system specific study monitoring.

( D) Your system specific study plan must specify the population served and system type ( subpart H or ground water).

( E) You must retain a complete copy of your system specific study plan submitted under this paragraph ( a)( 1), including any State modification of your system specific study plan, for as long as you are required to retain your IDSE report under paragraph ( b)( 5) of this section.

( F) If a you submit previously collected data that fully meet the number of samples required under paragraph ( a)( 1)( i)( B) of this section and the State rejects some of the data, you must either conduct additional monitoring to replace rejected data on a schedule the State approves or conduct standard monitoring under § 141.601.

( 2) Modeling. You may comply through analysis of an extended period simulation hydraulic model. The extended period simulation hydraulic model and analysis must meet the criteria in this paragraph ( a)( 2).

( i) Minimum requirements. ( A) The model must simulate 24 hour variation in demand and show a consistently repeating 24 hour pattern of residence time.

( B) The model must represent the criteria listed in paragraphs ( a)( 2)( i)( B)( 1) through ( 9) of this section.

( 1) 75% of pipe volume;

( 2) 50% of pipe length;

( 3) aAll pressure zones;

( 4) aAll 12 inch diameter and larger pipes;

( 5) aAll 8 inch and larger pipes that connect pressure zones, influence zones from different sources,

storage facilities, major demand areas, pumps, and control valves, or are known or expected to be significant conveyors of water;

( 6) aAll 6 inch and larger pipes that connect remote areas of a distribution system to the main portion of the system;

( 7) aAll storage facilities with standard operations represented in the model; and 317 ( 8) aAll active pump stations with controls represented in the model; and ( 9) aAll active control valves.

( C) The model must be calibrated, or have calibration plans, for the current configuration of the distribution system during the period of high TTHM formation potential. All storage facilities must be evaluated as part of the calibration process. All required calibration must be completed no later than 12 months after plan submission.

( ii) Reporting modeling. Your system specific study plan must include the information in this paragraph ( a)( 2)( ii).

( A) Tabular or spreadsheet data demonstrating that the model meets requirements in paragraph ( a)( 2)( i)( B) of this section.

( B) A description of all calibration activities undertaken, includingand if calibration is complete, a graph of predicted tank levels versus measured tank levels for the storage facility with the highest residence time in each pressure zone ( if calibration is complete), and a time series graph of the residence time at the longest residence time storage facility in the distribution system showing the predictions for the entire EPS simulation period ( i. e., from time zero until the time it takes to for the model to reach a consistently repeating pattern of residence time).

( C) Model output showing preliminary 24 hour average residence time predictions throughout the distribution system.

( D) Timing and number of samples representative of the distribution system planned for at least one roundmonitoring period of TTHM and HAA5 dual sample monitoring at a number of locations no less than would be required for the system under standard monitoring in § 141.601 during the historical month of high TTHM. These samples must be taken at locations other than existing subpart L compliance monitoring locations.

( E) Description of how all requirements will be completed no later than 12 months after you submit your system specific study plan. 318 ( F) Schematic of theyour distribution system ( including distribution system entry points and their sources,

and storage facilities), with notes indicating the locations and dates of all completed system specific study monitoring ( if calibration is complete) and all subpart L compliance monitoring.

( G) Population served and system type ( subpart H or ground water).

( H) You must retain a complete copy of your system specific study plan submitted under this paragraph ( a)( 2), including any State modification of your system specific study plan, for as long as you are required to retain your IDSE report under paragraph ( b)( 57) of this section.

( iii) If you submit a model that does not fully meet the requirements under paragraph ( a)( 2) of this section,

you must addresscorrect the deficiencies and respond to State inquiries concerning the model. If you fail to addresscorrect deficiencies or respond to inquiries to the State's satisfaction, you must conduct standard monitoring under § 141.601.

( b) IDSE report. Your IDSE report must include the elements required in paragraphs ( b)( 1) through ( b)( 56) of this section. You must submit your IDSE report according to the schedule in § 141.600( c).

( 1) Your IDSE report must include all TTHM and HAA5 analytical results from subpart L compliance monitoring and all system specific study monitoring conducted during the period of the system specific study presented in a tabular or spreadsheet format acceptable to the State. If changed from your system specific study plan submitted under paragraph ( a) of this section, your IDSE report must also include a schematic of your distribution system, the population served; and system type ( subpart H or ground water).

( 2) If you used the modeling provision under paragraph ( a)( 2) of this section, you must include final calibration information for the elements described in paragraph ( a)( 2)( ii)( B) of this section, and a 24 hour time series graph of residence time for each subpart V compliance monitoring location selected.

( 3) You must recommend and justify subpart V compliance monitoring locations and timing based on the protocol in § 141.605.

( 4) Your IDSE report must include an explanation of any deviations from your approved system specific 319 study plan.

( 45) Your IDSE report must include the basis ( analytical results and modeling results) and justification you used to select the recommended subpart V monitoring locations.

( 56) You may submit your IDSE report in lieu of your system specific study plan on the schedule identified in § 141.600( c) for submission of the system specific study plan if you believe that you have the necessary information by the time that the system specific study plan is due. If you elect this approach,

your IDSE report must also include all information required under paragraph ( a) of this section.

( 67) You must retain a complete copy of your IDSE report submitted under this section for 10 years after the date that you submitted your IDSE report. If the State modifies the subpart V monitoring requirements that you recommended in your IDSE report or if the State approves alternative monitoring locations, you must keep a copy of the State's notification on file for 10 years after the date of the State's notification.

You must make the IDSE report and any State notification available for review by the State or the public.

§ 141.603 40/ 30 certification.

( a) Eligibility. You are eligible for 40/ 30 certification if you have taken all requiredhad no TTHM or HAA5 monitoring violations under subpart L compliance samplesof this part and no individual sample exceeded 0.040 mg/ L for TTHM or 0.030 mg/ L for HAA5 during the periodan eight consecutive calendar quarter period beginning no earlier than the date specified in this paragraph ( a). 320 If your 40/ 30 Certification Is Due Then your eligibility for 40/ 30 certification is based on eight consecutive calendar quarters of subpart L compliance monitoring results during this periodbeginning no earlier than 1 ( 1) [ date six mos following publication of final rule] April 2004 March 2006( 2) [ date 12 mos following publication of final rule] October 2004 September1, 2006 January 2004 ( 32) [ date 18 mos following publication of final rule] April 2005 March1, 2007 January 2004 ( 43) [ date 24 mos following publication of final rule] October 2005 September1, 2007 January 2005 ( 4) April 1, 2008 January 2005 1 Unless you are on reduced monitoring under subpart L of this part and were not required to monitor during the specified period. If you did not monitor during the specified period, you must base your eligibility on compliance samples taken during the 12 months preceding the specified period.

( b) 40/ 30 certification. ( 1) You must certify to your State that every individual compliance sample taken under subpart L of this part during the periods specified in paragraph ( a) of this section were # 0.040 mg/ L for TTHM and # 0.030 mg/ L for HAA5. In addition,, and that you musthave not have had any TTHM or HAA5 monitoring violations during the period specified in paragraph ( a) of this section.

( 2) The State may require you to submit compliance monitoring results, distribution system schematics,

orand/ or recommended subpart V compliance monitoring locations in addition to your certification. If you fail to submit the requested information, the State may require standard monitoring under § 141.601 or a system specific study under § 141.602.

( 3) The State may still require standard monitoring under § 141.601 or a system specific study under § 141.602 even if you meet the criteria in paragraph ( a) of this section.

( 4) You must retain a complete copy of your certification submitted under this section for 10 years after the date that you submitted your certification. You must make the certification, all data upon which the certification is based, and any State notification available for review by the State or the public.

§ 141.604 Very small system waivers. 321 ( a) If you serve fewer than 500 people and you have taken TTHM and HAA5 samples under subpart L of this part, you are not required to comply with this subpart unless the State notifies you that you must conduct standard monitoring under § 141.601 or a system specific study under § 141.602.

( b) If you have not taken TTHM and HAA5 samples under subpart L of this part or if the State notifies you that you must comply with this subpart, you must conduct standard monitoring under § 141.601 or a system specific study under § 141.602.

§ 141.605 Subpart V compliance monitoring location recommendations.

( a) Your IDSE report must include your recommendations and justification for where and during what month( s) TTHM and HAA5 monitoring for subpart V of this part should be conducted. You must base your recommendations on the criteria in paragraphs ( b) through ( e) of this section.

( b) You must select the number of monitoring locations specified in the table in this paragraph ( b). You will use these recommended locations as subpart V routine compliance monitoring locations, unless State requires different or additional locations. You should distribute locations throughout the distribution system to the extent possible. 322 Source Water Type Population Size Category Monitoring Frequency 1 Distribution System Monitoring Location Total per monitoring period 2 Highest TTHM Locations Highest HAA5 Locations Existing Subpart L Compliance Locations Subpart H < 500 per year 2 2 1 1 !

500 3,300 per quarter 2 2 1 1 !

3,301 9,999 per quarter 2 1 1 !

10,000 49,999 per quarter 4 2 1 1 50,000 249,999 per quarter 8 3 3 2 250,000 999,999 per quarter 12 5 4 3 1,000,000 4,999,999 per quarter 16 6 6 4 $ 5,000,000 per quarter 20 8 7 5 Ground Water < 500 per year 2 2 1 1 !

500 9,999 per year 2 1 1 !

10,000 99,999 per quarter 4 2 1 1 100,000 499,999 per quarter 6 3 2 1 $ 500,000 per quarter 8 3 3 2 1 All systems must take at least one dual sample setmonitor during month of highest DBP concentrations. 2 Systems on quarterly monitoring must take dual sample sets every 90 days at each monitoring location, except for subpart H systems serving 500 3,300. 2 System iss on annual monitoring and subpart H systems serving 500 3,300 are required to take individual TTHM and HAA5 samples ( instead of a dual sample set) at the locations with the highest TTHM and HAA5 concentrations, respectively. Only one location with a dual sample set per monitoring period is needed if highest TTHM and HAA5 concentrations occur at the same location, and month, if monitored annually).

( c) You must recommend subpart V compliance monitoring locations based on standard monitoring results, system specific study results, and subpart L compliance monitoring results. You must follow the protocol in paragraphs ( c)( 1) through ( 4c)( 8) of this section. If required to monitor at more than foureight locations, you must repeat the protocol as necessary, alternating between locations with the highest HAA5 LRAA and the highest TTHM LRAA not previously selected as a subpart V monitoring location for choosing locations under paragraphs ( c)( 3) and ( c)( 4). If you do not have existing subpart L compliance 323 monitoring results or if you do not have enough existing subpart L compliance monitoring results, you must repeat the protocol as necessary using, skipping the provisions of paragraphs ( c)( 13), ( c)( 2), and ( c)( 47) of this section as necessary, until you have identified the required total number of monitoring locations.

( 1) Location with the highest TTHM LRAA not previously selected as a subpart V monitoring location.

( 2) Location with the highest HAA5 LRAA not previously selected as a subpart V monitoring location.

( 3) Existing subpart L average residence time compliance monitoring location ( maximum residence time compliance monitoring location for ground water systems) with the highest HAA5 LRAA not previously selected as a subpart V monitoring location.

( 4) Location with the highest TTHM LRAA not previously selected as a subpart V monitoring location.

( 5) Location with the highest TTHM LRAA not previously selected as a subpart V monitoring location.

( 6) Location with the highest HAA5 LRAA not previously selected as a subpart V monitoring location.

( 7) Existing subpart L average residence time compliance monitoring location ( maximum residence time compliance monitoring location for ground water systems) with the highest TTHM LRAA not previously selected as a subpart V monitoring location.

( 8) Location with the highest HAA5 LRAA not previously selected as a subpart V monitoring location.

( d) You may recommend locations other than those specified in paragraph ( c) of this section if you include a rationale for selecting other locations. If the State approves the alternate locations, you must monitor at these locations to determine compliance under subpart V of this part.

( e) Your recommended schedule must include subpart V monitoring during the peak historical month for TTHM and HAA5 concentration, unless the State approves another month. Once you have identified the peak historical month, and if you are required to conduct routine monitoring at least quarterly, you must schedule subpart V compliance monitoring at a regular frequency of every 90 days or fewer.

20. Part 141 is amended by adding new subpart V to read as follows: 324 Subpart V Stage 2 Disinfection Byproducts Requirements Sec.

141.620 General requirements.

141.621 Routine monitoring.

141.622 Subpart V monitoring plan.

141.623 Reduced monitoring.

141.624 Additional requirements for consecutive systems.

141.625 Conditions requiring increased monitoring.

141.626 Operational evaluation levels.

141.627 Requirements for remaining on reduced TTHM and HAA5 monitoring based on subpart L results.

141.628 Requirements for remaining on increased TTHM and HAA5 monitoring based on subpart L results.

141.629 Reporting and recordkeeping requirements.

Subpart V Stage 2 Disinfection Byproducts Requirements § 141.620 General requirements.

( a) The requirements of subpart V of this part constitute national primary drinking water regulations.

The regulations in this subpart establish monitoring and other requirements for achieving compliance with maximum contaminant levels based on locational running annual averages ( LRAA) for total trihalomethanes ( TTHM) and haloacetic acids ( five)( HAA5), and for achieving compliance with maximum residual disinfectant residuals for chlorine and chloramine for certain consecutive systems.

( b) Applicability. You are subject to these requirements if your system is a community water system or a nontransient noncommunity water system that uses a primary or residual disinfectant other than ultraviolet light or delivers water that has been treated with a primary or residual disinfectant other than ultraviolet 325 light.

( c) Schedule. You must comply with the requirements in this subpart on the schedule in the following table based on your system type.

IF YOU ARE THIS TYPE OF SYSTEM YOU MUST COMPLY WITH SUBPART V MONITORING BY: 1 Systems that are not part of a combined distribution system and systems that serve the largest population in the combined distribution system ( 1) System serving $ 100,000 [ date 72 mos following publication of final rule] April 1, 2012 ( 2) System serving 50,000 99,999 [ date 78 mos following publication of final rule] October 1, 2012 ( 3) System serving 10,000 49,999 [ date 90 mos following publication of final rule] October 1, 2013 ( 4) System serving < 10,000 [ date 90 mos following publication of final rule] October 1, 2013 if no Cryptosporidium monitoring is required under § 141.701( a)( 4) OR October 1, 2014 if Cryptosporidium monitoring is required under § 141.701( a)( 4) OR [ date 102 mos following publication of final rule] if Cryptosporidium monitoring is required under § 141.701or ( a)( 6)

Other systems that are part of a combined distribution system ( 5) Consecutive system or wholesale system  at the same time as the system with the earliest compliance date in the combined distribution system 1 The State may grant up to an additional 24 months for compliance with MCLs and operational evaluation levels if you require capital improvements to comply with an MCL.

( 6) Your monitoring frequency is specified in § 141.621( a)( 2).

( i) If you are required to conduct quarterly monitoring, you must begin monitoring in the first full calendar quarter that followsincludes the compliance date in the table in this paragraph ( c).

( ii) If you are required to conduct monitoring at a frequency that is less than quarterly, you must begin monitoring in the calendar month recommended in the IDSE report prepared under § 141.601 or § 141.602 or the calendar month identified in the subpart V monitoring plan developed under § 141.622 no later than 326 12 months after the compliance date in this table.

( 7) If you are required to conduct quarterly monitoring, you must make compliance calculations at the end of the fourth calendar quarter that follows the compliance date and at the end of each subsequent quarter ( or earlier if the LRAA calculated based on fewer than four quarters of data would cause the MCL to be exceeded regardless of the monitoring results of subsequent quarters). If you are required to conduct monitoring at a frequency that is less than quarterly, you must make compliance calculations beginning with the first compliance sample taken after the compliance date.

( 8) For the purpose of the schedule in this paragraph ( c), the State may determine that the combined distribution system does not include certain consecutive systems based on factors such as receiving water from a wholesale system only on an emergency basis or receiving only a small percentage and small volume of water from a wholesale system. The State may also determine that the combined distribution system does not include certain wholesale systems based on factors such as delivering water to a consecutive system only on an emergency basis or delivering only a small percentage and small volume of water to a consecutive system.

( d) Monitoring and compliance.

( 1) Systems required to monitor quarterly. To comply with subpart V MCLs in § 141.64( b)( 2), you must calculate LRAAs for TTHM and HAA5 using monitoring results collected under this subpart and determine that each LRAA does not exceed the MCL. If you fail to complete four consecutive quarters of monitoring, you must calculate compliance with the MCL based on the average of the available data from the most recent four quarters. If you take more than one sample per quarter at a monitoring location, you must average all samples taken in the quarter at that location to determine a quarterly average to be used in the LRAA calculation.

( 2) Systems required to monitor yearly or less frequently. To determine compliance with subpart V MCLs in § 141.64( b)( 2), you must determine that each sample taken is less than the MCL. If any sample 327 exceeds the MCL, you must comply with the requirements of § 141.625. If no sample exceeds the MCL,

the sample result for each monitoring location is considered the LRAA for that monitoring location.

( e) Failure to monitor will be treated as a monitoring violation for the entire period covered by a locational running annual average compliance calculation for the subpart V MCLs in § 141.64( b)( 2). You are in violation of the monitoring requirements for each quarter that a monitoring result would be used in calculating an LRAA if you fail to monitor.

§ 141.621 Routine monitoring.

( a) Monitoring. ( 1) If you submitted an IDSE report, you must begin monitoring at the locations and months you have recommended in your IDSE report submitted under § 141.605 following the schedule in § 141.620( c), unless the State requires other locations or additional locations after its review. If you submitted a 40/ 30 certification under § 141.603 or you qualified for a very small system waiver under § 141.604 or you are a nontransient noncommunity water system serving < 10,000, you must monitor at the location( s) and dates identified in your monitoring plan in § 141.132( f), updated as required by § 141.622.

( 2) You must monitor at no fewer than the number of locations identified in this paragraph ( a)( 2). 328 Source Water Type Population Size Category Monitoring Frequency 1 Distribution System Monitoring Location Total per Monitoring Period 2 Subpart H < 500 per year 2 2 500 3,300 per quarter 2 2 3,301 9,999 per quarter 2 10,000 49,999 per quarter 4 50,000 249,999 per quarter 8 250,000 999,999 per quarter 12 1,000,000 4,999,999 per quarter 16 $ 5,000,000 per quarter 20 Ground Water < 500 per year 2 2 500 9,999 per year 2 10,000 99,999 per quarter 4 100,000 499,999 per quarter 6 $ 500,000 per quarter 8 1 All systems must take at least one dual sample setmonitor during month of highest DBP concentrations. 2 Systems on quarterly monitoring must take dual sample sets every 90 days at each monitoring location, except for subpart H systems serving 500 3,300. 2 System iss on annual monitoring and subpart H systems serving 500 3,300 are required to take individual TTHM and HAA5 samples ( instead of a dual sample set) at the locations with the highest TTHM and HAA5 concentrations, respectively. Only one location with a dual sample set per monitoring period is needed if highest TTHM and HAA5 concentrations occur at the same location ( and month, if monitored annually).

( 3) If you are an undisinfected system that begins using a disinfectant other than UV light after the dates in subpart U of this part for complying with the Initial Distribution System Evaluation requirements, you must consult with the State to identify compliance monitoring locations for this subpart. You must then develop a monitoring plan under § 141.622 that includes those monitoring locations.

( b) Analytical methods. You must use an approved method listed in § 141.131 for TTHM and HAA5 analyses in this subpart. Analyses must be conducted by laboratories that have received certification by EPA or the State as specified in § 141.131. 329 § 141.622 Subpart V monitoring plan.

( a) Subpart V monitoring plan. ( 1) You must develop and implement a monitoring plan to be kept on file for State and public review. The monitoring plan must contain the elements in paragraphs ( a)( 1)( i) through ( a)( 1)( iv) of this section and be complete no later than the date you conduct your initial monitoring under this subpart.

( i) mMonitoring locations;

( ii) mMonitoring dates;

( iii) cCompliance calculation procedures; and ( iv) mMonitoring plans for any other systems in the combined distribution system if the State has reduced monitoring requirements under the State authority in § 142.16( m).

( 2) If you were not required to submit an IDSE report under either § 141.601 or § 141.602, and you do not have sufficient subpart L monitoring locations to identify the required number of subpart V compliance monitoring locations indicated in § 141.605( b), you must identify additional locations by alternating selection of locations representing high TTHM levels and high HAA5 levels until the required number of compliance monitoring locations have been identified. You must also provide the rationale for identifying the locations as having high levels of TTHM or HAA5. If you have more subpart L monitoring locations than required for subpart V compliance monitoring in § 141.605( b), you must identify which locations you will use for subpart V compliance monitoring by alternating selection of locations representing high TTHM levels and high HAA5 levels until the required number of subpart V compliance monitoring locations have been identified.

( b) If you are a subpart H system serving > 3,300 people, you must submit a copy of your monitoring plan to the State prior to the date you conduct your initial monitoring under this subpart, unless your IDSE report submitted under subpart U of this part contains all the information required by this section.

( c) You may revise your monitoring plan to reflect changes in treatment, distribution system operations 330 and layout ( including new service areas), or other factors that may affect TTHM or HAA5 formation, or for State approved reasons, after consultation with the State regarding the need for changes and the appropriateness of changes. If you change monitoring locations, you must replace existing compliance monitoring locations with the lowest LRAA with new locations that reflect the current distribution system locations with expected high TTHM or HAA5 levels. The State may also require modifications in your monitoring plan. If you are a subpart H system serving > 3,300 people, you must submit a copy of your modified monitoring plan to the State prior to the date you are required to comply with the revised monitoring plan.

§ 141.623 Reduced monitoring.

( a) You may reduce monitoring to the level specified in the table in this paragraph ( a) any time the LRAA is # 0.040 mg/ L for TTHM and # 0.030 mg/ L for HAA5 at all monitoring locations. You may only use data collected under the provisions of this subpart or subpart L of this part to qualify for reduced monitoring. In addition, the source water annual average TOC level, before any treatment, must be # 4.0 mg/ L at each treatment plant treating surface water or ground water under the direct influence of surface water, based on monitoring conducted under either § 141.132( b)( 1)( iii) or § 141.132( d). 331 Source Water Type Population Size Category Monitoring Frequency 1 Distribution System Monitoring Location per Monitoring Period Subpart H < 500  monitoring may not be reduced 500 3,300 per year 1 TTHM and 1 HAA5 sample: one at the location and during the quarter with the highest TTHM single measurement, one at the location and during the quarter with the highest HAA5 single measurement; 1 dual sample set per year if the highest TTHM and HAA5 measurements occurred at the same location and quarter.

3,301 9,999 per year 2 dual sample sets: one at the location and during the quarter with the highest TTHM single measurement, one at the location and during the quarter with the highest HAA5 single measurement 10,000 49,999 per quarter 2 dual sample sets at the locations with the highest TTHM and highest HAA5 LRAAs 50,000 249,999 per quarter 4 dual sample sets  at the locations with the two highest TTHM and two highest HAA5 LRAAs 250,000 999,999 per quarter 6 dual sample sets  at the locations with the three highest TTHM and three highest HAA5 LRAAs 1,000,000 4,999,999 per quarter 8 dual sample sets  at the locations with the four highest TTHM and four highest HAA5 LRAAs $ 5,000,000 per quarter 10 dual sample sets  at the locations with the five highest TTHM and five highest HAA5 LRAAs Ground Water < 500 every third year 1 TTHM and 1 HAA5 sample: one at the location and during the quarter with the highest TTHM single measurement, one at the location and during the quarter with the highest HAA5 single measurement; 1 dual sample set per year if the highest TTHM and HAA5 measurements occurred at the same location and quarter.

500 9,999 per year 1 TTHM and 1 HAA5 sample: one at the location and during the quarter with the highest TTHM single measurement, one at the location and during the quarter with the highest HAA5 single measurement; 1 dual sample set per year if the highest TTHM and HAA5 measurements occurred at the same location and quarter.

10,000 99,999 per year 2 dual sample sets: one at the location and during the quarter with the highest TTHM single measurement, one at the location and during the quarter with the highest HAA5 single measurement 100,000 499,999 per quarter 2 dual sample sets; at the locations with the highest TTHM and highest HAA5 LRAAs $ 500,000 per quarter 4 dual sample sets at the locations with the two highest TTHM 332 1 Systems on quarterly monitoring must take dual sample sets every 90 days.

( b) You may remain on reduced monitoring as long as the TTHM LRAA # 0.040 mg/ L and the HAA5 LRAA # 0.030 mg/ L at each monitoring location ( for systems with quarterly reduced monitoring) or each TTHM sample # 0.060 mg/ L and each HAA5 sample # 0.045 mg/ L ( for systems with annual or less frequent monitoring). In addition, the source water annual average TOC level, before any treatment, must be # 4.0 mg/ L at each treatment plant treating surface water or ground water under the direct influence of surface water, based on monitoring conducted under either § 141.132( b)( 1)( iii) or § 141.132( d).

( c) If the LRAA based on quarterly monitoring at any monitoring location exceeds either 0.040 mg/ L for TTHM or 0.030 mg/ L for HAA5 or if the annual ( or less frequent) sample at any location exceeds either 0.060 mg/ L for TTHM or 0.045 mg/ L for HAA5, or if the source water annual average TOC level, before any treatment, > 4.0 mg/ L at any treatment plant treating surface water or ground water under the direct influence of surface water, you must resume routine monitoring under § 141.621 or begin increased monitoring if § 141.625 applies.

( c) The State may return your system to routine monitoring at the State's discretion.

§ 141.624 Additional requirements for consecutive systems.

If you are a consecutive system that does not add a disinfectant but delivers water that has been disinfected with treatmenttreated with a primary or residual disinfectant other than ultraviolet light, you must comply with analytical and monitoring requirements for chlorine and chloramines in § § 141 § 141.131 ( c) and 141 § 141.132( c)( 1) and the compliance requirements in § 141.133( c)( 1) beginning [ DATE THREE YEARS AFTER PUBLICATION OF FINAL RULE] April 1, 2009, unless required earlier by the State, and report monitoring results under § 141.134( c).

§ 141.625 Conditions requiring increased monitoring. 333 ( a) If you are required to monitor at a particular location annually or less frequently than annually under § § 141 § 141.621 or 141 § 141.623, you must increase monitoring to dual sample sets once per quarter ( taken every 90 days) at all locations if a TTHM sample is > 0.080 mg/ L or a HAA5 sample is > 0.060 mg/ L at any location.

( b) You are in violation of the MCL when the LRAA exceeds the subpart V MCLs in § 141.64( b)( 2),

calculated based on four consecutive quarters of monitoring ( or the LRAA calculated based on fewer than four quarters of data if the MCL would be exceeded regardless of the monitoring results of subsequent quarters). You are in violation of the monitoring requirements for each quarter that a monitoring result would be used in calculating an LRAA if you fail to monitor.

( c) You may return to routine monitoring once you have conducted increased monitoring for at least four consecutive quarters and the LRAA for every monitoring location is # 0.060 mg/ L for TTHM and # 0.045 mg/ L for HAA5.

§ 141.626 Operational evaluation levels.

( a) You have exceeded the operational evaluation level at any monitoring location where the sum of the two previous quarters' TTHM results plus twice the current quarter's TTHM result , divided by 4 to determine an average, exceeds 0.080 mg/ L, or where the sum of the two previous quarters' HAA5 results plus twice the current quarter's HAA5 result, divided by 4 to determine an average, exceeds 0.060 mg/ L.

( b) Operational evaluation.

( 1) If you exceed the operational evaluation level, you must conduct an operational evaluation and submit a written report of the evaluation to the State no later than 90 days after being notified of the analytical result that causes you to exceed the operational evaluation level. The written report must be made available to the public upon request.

( 2) Your operational evaluation must include an examination of system treatment and distribution 334 operational practices, including storage tank operations, excess storage capacity, distribution system flushing, changes in sources or source water quality, and treatment changes or problems that may contribute to TTHM and HAA5 formation and what steps could be considered to minimize future exceedences.

( i) You may request and the State may allow you to limit the scope of your evaluation if you are able to identify the cause of the operational evaluation level exceedance.

( ii) Your request to limit the scope of the evaluation does not extend the schedule in paragraph ( b)( 1) of this section for submitting the written report. The State must approve this limited scope of evaluation in writing and you must keep that approval with the completed report.

§ 141.627 Requirements for remaining on reduced TTHM and HAA5 monitoring based on subpart L results.

You may remain on reduced monitoring after the dates identified in § 141.620( c) for compliance with this subpart only if you qualify for a 40/ 30 certification under § 141.603 or have received a very small system waiver under § 141.604, plus you meet the reduced monitoring criteria in § 141.623( a), and you do not change or add monitoring locations from those used for compliance monitoring under subpart L of this part. If your monitoring locations under this subpart differ from your monitoring locations under subpart L of this part, you may not remain on reduced monitoring after the dates identified in § 141.620( c) for compliance with this subpart.

§ 141.628 Requirements for remaining on increased TTHM and HAA5 monitoring based on subpart L results.

If you were on increased monitoring under § 141.132( b)( 1), you must remain on increased monitoring until you qualify for a return to routine monitoring under § 141.625( c). You must conduct increased monitoring 335 under § 141.625 at the monitoring locations in the monitoring plan developed under § 141.622 beginning at the date identified in § 141.620( c) for compliance with this subpart and remain on increased monitoring until you qualify for a return to routine monitoring under § 141.625( c).

§ 141.629 Reporting and recordkeeping requirements.

( a) Reporting. ( 1) You must report the following information for each monitoring location to the State within 10 days of the end of any quarter in which monitoring is required:

( i) Number of samples taken during the last quarter.

( ii) Date and results of each sample taken during the last quarter.

( iii) Arithmetic average of quarterly results for the last four quarters for each monitoring location ( LRAA), beginning at the end of the fourth calendar quarter that follows the compliance date and at the end of each subsequent quarter. If the LRAA calculated based on fewer than four quarters of data would cause the MCL to be exceeded regardless of the monitoring results of subsequent quarters, you must report this information to the State as part of the first report due following the compliance date or anytime thereafter that this determination is made. If you are required to conduct monitoring at a frequency that is less than quarterly, you must make compliance calculations beginning with the first compliance sample taken after the compliance date, unless you are required to conduct increased monitoring under § 141.625.

( iv) Whether, based on § 141.64( b)( 2) and this subpart, the MCL was violated at any monitoring location.

( v) Any operational evaluation levels that were exceeded during the quarter and, if so, the location and date, and the calculated TTHM and HAA5 levels.

( 2) If you are a subpart H system seeking to qualify for or remain on reduced TTHM/ HAA5 monitoring,

you must report the following source water TOC information for each treatment plant that treats surface water or ground water under the direct influence of surface water to the State within 10 days of the end of any quarter in which monitoring is required: 336 ( i) The number of source water TOC samples taken each month during last quarter.

( ii) The date and result of each sample taken during last quarter.

( iii) The quarterly average of monthly samples taken during last quarter or the result of the quarterly sample.

( iv) The running annual average ( RAA) of quarterly averages from the past four quarters.

( v) Whether the RAA exceeded 4.0 mg/ L.

( 3) The State may choose to perform calculations and determine whether the MCL was exceeded or the system is eligible for reduced monitoring in lieu of having the system report that information ( b) Recordkeeping. You must retain any subpart V monitoring plans and your subpart V monitoring results as required by § 141.33.

PART 142  National Primary Drinking Water Regulations Implementation 21. The authority citation for part 142 continues to read as follows:

Authority: 42 U. S. C. 300f, 300g 1, 300g 2, 300g 3, 300g 4, 300g 5, 300g 6, 300j 4, 300j 9, and 300j 11.

22. Section 142.14 is amended by adding paragraph ( a)( 8) to read as follows:

§ 142.14 Records kept by States.

( a) ***

( 8) Any decisions made pursuant to the provisions of 40 CFR part 141, subparts U and V of this part.

( i) IDSE monitoring plans, plus any modifications required by the State, must be kept until replaced by approved IDSE reports.

( ii) IDSE reports and 40/ 30 certifications, plus any modifications required by the State, must be kept 337 until replaced or revised in their entirety.

( iii) Operational evaluations submitted by a system must be kept for 10 years following submission.

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23. Section 142.16 is amended by adding paragraph ( m) to read as follows:

§ 142.16 Special primacy conditions.

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( m) Requirements for States to adopt 40 CFR part 141, subparts U and V. In addition to the general primacy requirements elsewhere in this part, including the requirements that State regulations be at least as stringent as federal requirements, an application for approval of a State program revision that adopts 40 CFR part 141, subparts U and V, must contain a description of how the State will implement a procedure for addressing modification of wholesale system and consecutive system monitoring on a case by case basis for part 141 subpart V outside the provisions of § 141.29 of this chapter, if the State elects to use such an authority. The procedure must ensure that all systems have at least one compliance monitoring location.

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