Exhibit A-6-12 Bottom Line Burden Hours and Costs for EPA (including EPA's contractor)
                                Respondent Type
                                 Burden Hours
                                  Total Costs
EPA
                                                                          8,735
                                                                       $615,658
Contractor
                                                                         27,685
                                                                     $2,338,275
TOTAL
                                                                         36,420
                                                                     $2,953,933

Exhibit A-6-13 shows the bottom line hour and dollar burden estimate by the Information Collection (IC) Entities. IC Entities covered by this ICR include publicly owned CWSs, privately/investor owned CWSs, state owned CWSs and state government agencies.

Exhibit A-6-13 Disaggregated Burden by Affected Information Collection (IC) Entities

                          Total Number Of IC Entities
                              Burden Per Response
                               Total Hour Burden
                                  Hourly Rate
                                  Total Cost
                               Cost Per Response
Water Systems Respondents
Serving More than 50,000 Persons
Publicly Owned CWSs
                                                                           785
                                                                           6.48
                                                                         5,087
                                                                         $42.59
                                                                       $216,655
                                                                         $ 276

Private/Investor Owned CWSs
                                                                           131

                                                                           849

                                                                        $36,159

State Owned CWSs
                                                                             4

                                                                            26

                                                                         $1,107

Tribal Owned CWSs & NPNCWSs
                                                                           -

                                                                           -

                                                                             $0

Subtotal
                                                                           920

                                                                         5,962

                                                                       $253,922

Serving 3,301 to 50,000 Persons
Publicly Owned CWSs
                                                                         1,674
                                                                          5.09

                                                                         8,512
                                                                         $35.49
                                                                       $302,091
                                                                         $ 180

Private/Investor Owned CWSs
                                                                           244

                                                                         1,241

                                                                        $44,043

State Owned CWSs
                                                                            21

                                                                           107

                                                                         $3,797

Tribal Owned CWSs & NPNCWSs
                                                                           -
                                                                           -
                                                                           -

                                                                             $-
                                                                              -

Subtotal
                                                                         1,939
                                                                          5.09
                                                                         9,860

                                                                       $349,931
                                                                          $ 180
Serving 3,300 and Fewer Persons
Publicly Owned CWSs
                                                                             -
                                                                              -
                                                                             -
                                                                              -
                                                                           $ -
                                                                           $ -

Private/Investor Owned CWSs
                                                                             -

                                                                             -

                                                                           $ -

State Owned CWSs
                                                                             -

                                                                             -

                                                                           $ -

Tribal Owned CWSs & NPNCWSs
                                                                             -

                                                                              -

                                                                           $ -

Subtotal
                                                                             -

                                                                             -

                                                                           $ -

Total Water System Respondents

Publicly Owned CWSs
                                                                         2,459
                                                                          5.53
                                                                        13,599

                                                                       $518,746
                                                                         $ 211

Private/Investor Owned CWSs
                                                                           375
                                                                          5.57
                                                                         2,090

                                                                        $80,202
                                                                         $ 214

State Owned CWSs
                                                                            25
                                                                          5.32
                                                                           133

                                                                         $4,904
                                                                         $ 196

Tribal Owned CWSs & NPNCWSs
                                                                           -
                                                                             -
                                                                           -

                                                                             $-
                                                                              -

Subtotal
                                                                         2,859
                                                                          5.53
                                                                        15,822

                                                                       $603,853
                                                                         $ 211
Total State Government Respondents
                                                                            56
                                                                         381.64
                                                                         21,372
                                                                        $ 52.88
                                                                   $ 1,130,151
                                                                      $ 20,181
Total Tribal Authority Respondents
                                                                             -
                                                                              -
                                                                              -
                                                                            $ -
                                                                            $ -
                                                                           $ -
Total Respondents
                                                                         2,915
                                                                         12.76
                                                                        37,194

                                                                  $ 1,734,004
                                                                          $ 595
Note: 	Numbers may not add due to rounding.

A.6.f	Reasons for Change in Burden
This ICR does not modify an existing ICR. However, it should be noted that an ICR was prepared for the previous survey effort done in 2011, which is outside of the three-year window for modifying an existing ICR for a new effort. For purposes of this reinstatement, the EPA has provided a comparison of burden of the proposed new effort to the estimates of the previous 2011 effort's ICR.
The estimated total public reporting burden over the entire four-year length of the 2011 DWINSA was 48,995 hours; the total burden for the 2015 Survey is estimated to be 37,194 hours.  The 2011 DWINS average burden per respondent was estimated to be 15.24 hours whereas for 2015 the average is estimated to be 12.76 hours per respondent. The reduction in burden for the 2015 DWINSA is attributed to:
   1. The use of a modified data collection approach, whereby a majority of systems from the 2011 DWINSA are being resurveyed and a smaller pool of systems will be randomly surveyed.
   2. For the 2015 DWINSA, existing data from the 2011 DWINSA for Tribal systems will be extrapolated to 2015 needs using construction cost inflation calculations and taking into account any shifts in the number and size of these systems.
A.6.g	Burden Statement
The public reporting burden for collections included in this ICR is detailed above. The total public reporting burden over the four-year length of the 2011 DWINSA is estimated to be 37,194 hours, of which 15,822 hours are attributable to water systems. These estimates include time for gathering and submitting of information. Public reporting burden (i.e., combined state and system burden) for this collection of information is estimated to average 12.76 hours per response. Respondent burden for the water system alone is 5.53 hours per system response.
Burden means the total time, effort or financial resources expended by people to generate, maintain, retain, disclose or provide information to or for a federal agency. This includes the time needed to review instructions, adjust the existing ways to comply with any previously applicable instructions and requirements, train personnel to respond to the information collection request, search data sources, complete and review the collection of information and transmit or otherwise disclose the information. An agency may not conduct or sponsor, and a person is not required to respond to, a request for information collection unless it displays a currently valid OMB control number. The OMB control numbers for EPA's regulations are listed in 40 CFR Part 9 and 48 CFR Chapter 15.
Please send comments on the Agency's need for this information, accuracy of the burden estimates and any suggested methods for minimizing respondent burden to: Director, Office of Environmental Information, Collection Strategies Division, U.S. Environmental Protection Agency (2822T), Ariel Rios Building, 1200 Pennsylvania Ave., N.W., Washington, D.C. 20460; and to the Office of Information and Regulatory Affairs, Office of Management and Budget, 725 17th Street, NW, Washington, DC 20503, Attention: Desk Officer for EPA. Please include the EPA ICR number and OMB control number in any correspondence.

PART B OF THE SUPPORTING STATEMENT (FOR STATISTICAL SURVEYS)

                            INTRODUCTION TO PART B
The Environmental Protection Agency (EPA) will conduct the following type of statistical survey for the 2015 State Drinking Water Infrastructure Needs Survey and Assessment (DWINSA). EPA will undertake an assessment of community water systems (CWSs) serving populations of more than 3,300. EPA will use the same methodology for collecting data for CWSs serving more than 3,300 persons as was used in the 2011 DWINSA with the implementation of a modified panel approach. EPA will not be collecting new data from the field for CWSs serving 3,300 and fewer or from American Indian systems, Alaska Native Village water systems or not-for-profit noncommunity water systems; instead, the Agency will update the data from previous surveys based on construction cost inflation and on shifts in the number and sizes of these water systems.

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2015 DWINSA
B.1	SURVEY OBJECTIVES, KEY VARIABLES AND OTHER PRELIMINARIES
B.1.a	Survey Objectives
The primary objective of the 2015 DWINSA is to collect information from water systems on the infrastructure they need to continue to provide safe drinking water to consumers. These data are used to produce a national estimate as well as state-specific estimates of water systems' 20-year need. EPA has established policies to ensure that the overarching goals of the survey are met:
 Estimate the total national 20-year need
 Estimate the total 20-year need for each fully participating state
 Provide complete and accurate data to Congress
 Provide a tool to fairly distribute DWSRF capitalization funds to states
 Maintain the credibility of the DWINSA findings
EPA proposes to collect information on the cost of water systems' infrastructure needs. If cost data are not available from systems, EPA proposes to collect information that will enable the Agency to model costs. In the data collection instrument, the respondent will identify needs on a project-by-project basis and list the "type(s) of need" that the project will meet. The "types of need" include raw water source, transmission, source water treatment, storage, distribution, pumping stations and other needs.
EPA will use the information from the DWINSA to estimate capital investment requirements of drinking water systems. The information will be used to allot DWSRF monies among states and as part of an allotment formula for the DWSRF Tribal Set-Aside (TSA) Program.
For the 2015 DWINSA, EPA is proposing to use a modified panel approach to select survey respondents. The modified panel approach will involve dropping a random selection of 25 percent of the systems serving 3,301 to 100,000 people that participated in the 2011 DWINSA and then drawing a random sample to replace those systems in the survey for the 2015 DWINSA. This will be done for each state and by strata. By primarily using information from the 2011 DWINSA, this approach would reduce the amount of time required to prepare and review the responses from systems resurveyed in 2015.
For the new systems selected for the 2015 Assessment, EPA will use the same methodology as used in previous DWINSAs. The sampling design is discussed in detail below.
B.1.b	Key Variables
Several key variables are available from the Safe Drinking Water Information System (SDWIS). To ensure accuracy, the 2015 DWINSA will verify these data by asking respondents to confirm existing information (pre-populated on the data collection instrument) or correct it. These variables include population served, total design capacity, number of service connections, primary source of supply, ownership type (private or public) and whether the system purchases water from or sells water to another water system.
Information on capital needs will be collected from respondents on a project-by-project basis. For each project, respondents will be asked to provide the following types of information: type of need; reason for need; documentation of need and cost (if necessary); if the project is a new project or to replace, rehabilitate or expand existing infrastructure; if the project is needed now to protect public health or if it is needed over the next 20 years to continue to provide safe drinking water; the federal regulation or state requirement (if the project is to meet a current regulation or state requirement); design capacity of source, storage and treatment projects; length and diameter of pipe projects; diameter for projects such as water meters; cost of the project (if available); and date of the cost estimate. For most of these variables, respondents will choose the appropriate "documentation," "type of need," "reason for need" or "regulation or requirement" from EPA's Lists of Codes.
The principal variable of interest is total projected capital needed for each water system in the 2015 DWINSA for the time period of January 1, 2015, through December 31, 2034. The total capital need for all systems in each state (to be derived from the statistical sample of systems) is the key variable that decision-makers at EPA use to allocate funds to states based on need.
The method of data collection has been designed to minimize burden on respondents while ensuring that information is collected in a consistent manner. Collecting information on a project-by-project basis, for example, will be particularly helpful in reducing burden since most respondents develop Capital Improvement Plans (CIPs) on a project-by-project basis.
Information on type of need will be used to disaggregate total capital needs for EPA's Report to Congress. Information on the reason for need will be used to verify the public health benefit of the need. Information on the date of the cost estimate will be used to provide a consistent basis for cost estimates across systems. Information on a regulation or requirement will be used to determine the reported project costs related to federal regulations or state requirements.
If a system cannot provide cost estimates, additional data are necessary so that the Agency can impute costs. Each of these variables is described in greater detail later in this document.
B.1.c	Statistical Approach
The 2015 DWINSA is being designed to achieve a desired level of precision for state-level estimates of total capital needs for systems serving more than 3,300 persons. EPA proposes a modified panel approach that includes a census of large systems and a survey of a statistical sample of medium-sized systems to estimate total capital needs. This statistical approach minimizes burden while achieving the desired level of precision.
The 2015 DWINSA design divides CWSs serving populations of more than 3,300 into two groups: CWSs serving populations of more than 100,000 and systems serving populations of 3,301 to 100,000. EPA proposes to sample with certainty systems serving more than 100,000 persons. These systems have the largest capital needs and they have the staff to respond efficiently to the 2015 DWINSA. EPA proposes to use a random sample of systems serving 3,301 to 100,000 persons. This methodology can reduce burden and still achieve the DWINSA data quality objectives.
To further reduce burden, EPA proposes using a modified panel approach for the 2015 DWINSA.  Rather than select a completely new sample of systems in 2015, EPA will reassess the needs of most of the systems that participated in the 2011 Assessment. EPA will replace 25 percent of the sample of systems serving 3,301 to 100,000 people. By state and stratum, EPA will randomly select 25 percent of the sample to drop and will then randomly select replacement systems from the sampling frame. By primarily using information from the 2011 DWINSA, this approach would reduce the amount of time required for systems to prepare and states to review the responses from systems resurveyed in 2015. This approach will maintain EPA's sampling targets for each stratum and ensure that EPA continues to meet its precision targets for each state. Additionally, by using information from the 2011 review, the modified panel approach would reduce the amount of time required for EPA's contractor to review each system's response. By replacing 25 percent of the sample, EPA will reduce a potential source of bias introduced by the panel. (When a completely new sample was selected for each assessment, the sampling error was a random component that changed from survey to survey. With the panel approach, this error becomes systematic.) By refreshing 25 percent of the sample, the approach alleviates this potential source of bias and helps to ensure that the 2015 sample represents the need as it exists in 2015.
To meet the state-level precision targets, EPA will use the same strata as in the 2011 DWINSA. As previously mentioned, EPA will adjust the sample size to accommodate changes in the sample frame. These changes may address new systems, systems that are no longer active and systems that have "migrated" between strata (become smaller or larger, or changed source). If EPA determines that there have been substantial changes in the size of the sample frame since the 2011 DWINSA, EPA will adjust the sample size as needed to ensure that the precision targets are met for each state. As in the 2011 DWINSA, EPA will first determine the total sample size for each state to meet the target level of precision. EPA will then allocate the sample to strata in order to maximize the efficiency of the design.
EPA is designing and conducting the 2015 DWINSA with the assistance of a contractor:
Contractor
The Cadmus Group, Inc.
100 5[th] Avenue, Suite 100
Waltham, MA 02451
(617) 673-7000

Contractor Roles
oo Oversight of data collection instrument design
oo Oversight of statistical sample design
oo Training
oo Data collection instrument package distribution: logistics
oo Technical support for respondents and states
oo Review of all survey responses for conformance to survey policies and project allowablity criteria
oo Model development
oo Data processing
oo Statistical sample design

B.1.d	Feasibility
The 2015 DWINSA data collection instrument has been designed with the capabilities of the typical respondent in mind. To fully assess feasibility, the Agency undertook the following steps. EPA convened a workgroup (see Section A.5.b) to comment on the proposed data collection and its feasibility. The data collection instrument to be used for the 2015 DWINSA is generally the same form as used for the past two DWINSAs. For the 2007 DWINSA, EPA conducted a pre-test in which EPA's contractor met with individual CWS operators and discussed the proposed survey. System operators were asked to comment on all proposed data elements and the feasibility of collecting information by a mail survey. The Agency recognizes that most systems serving fewer than 50,000 persons and some that serve 50,000 or more may not have cost data or documentation of costs for some projects. In those cases, the 2015 DWINSA data collection instrument requests other readily available information that EPA can use to model costs. EPA will emphasis to respondents that they are not expected to develop cost estimates for the purposes of the 2015 DWINSA. In addition, EPA (or states) will provide systems with technical assistance for completing the data collection instrument.
EPA has developed cost models for most of the infrastructure needs included in the 2015 DWINSA based on the size and capacity of a project. These cost models were originally developed during the 1995 DWINSA, have been updated during subsequent assessments, including the 2011 DWINSA, and will be used again for the 2015 DWINSA. New cost models may be developed for weaker cost models, influential cost models and new technology.
The time frame for the 2015 DWINSA is acceptable to the users of data within the Office of Ground Water and Drinking Water (OGWDW) and sufficient to complete a report to Congress by its anticipated due date of early 2017. The schedule also is acceptable to other users of the data.
B.2	SURVEY DESIGN
This section contains a detailed description of the statistical survey design and modified panel approach including a description of the sampling frame, sample identification, precision requirements and data collection instrument.
The sample design for the 2015 DWINSA is stratified random sampling within each state. In cases where the state is not participating in the data collection for systems serving 3,301 to 100,000 persons, EPA will not provide state-specific results, as the data collection for these states does not meet the DWINSA data quality objectives. EPA will include an overall national result for the systems serving 3,301 to 100,000 persons, using the average need by strata of the systems in states that are participating in the full 2015 DWINSA. For states that are fully participating in data collection for systems serving 3,301-100,000 persons, the 2015 DWINSA will use a modified panel approach for sampling these systems within each state. This approach is described in more detail in Section B.2.b.
Stratification increases the precision of estimates compared with a simple random sample of the target population of systems. In stratified samples, the target population is divided into non-overlapping groups, known as strata, from which separate samples are drawn. The goal of stratified sampling is to choose sample sizes within each stratum in a manner designed to obtain maximum precision in the overall estimate for the population. Stratification variables for this study include: population size (populations of: 3,301 to 10,000; 10,001 to 25,000; 25,001 to 50,000; 50,001 to 100,000 and more than 100,000) and primary sources of supply (surface and ground). Systems serving more than 100,000 persons are selected with certainty. For the 2011 DWINSA, the size of each state's sample of systems serving populations of 3,301 to 100,000 was set to meet the 2011 DWINSA's data quality objectives. For the 2015 DWINSA, the survey will rely on a modified panel approach in which 75 percent of the 2011 DWINSA respondents serving populations of 3,301 to 100,000 are resampled, and 25 percent are put back into the frame and a new 25 percent are drawn.
EPA's precision target for the 2015 DWINSA is to be 95 percent confident that the true need for each state lies within an interval of plus or minus 10 percent of the estimated need. These precision targets are identical to the targets for the 2011 Assessment. The 2011 sample, modified as described above, will meet the assessment's precision target. The sample sizes will be adjusted to account for changes in the inventory of systems, if necessary, to ensure the 2015 sample meets the precision targets.
B.2.a	Target Population and Coverage
The target population for the 2015 DWINSA is the number of CWSs in the nation. A CWS is a public water system (PWS) that serves at least 15 service connections used by year-round residents or regularly serves at least 25 year-round residents (40 CFR 141.2). The 2015 DWINSA is designed to produce estimates of the capital need of systems serving more than 3,300 persons for each participating state. In partially surveyed states, EPA will be able to provide state-specific results for systems serving 100,000 or more persons. EPA will include an overall national result for the systems serving 3,301 to 100,000 persons using the average need by strata of the systems in participating states and the total number of systems by strata in the partially surveyed state. The 2015 DWINSA is designed to produce estimates of the capital need of systems serving 3,300 and fewer persons by state and for the nation as a whole using the results of the 2007 DWINSA.
B.2.b	Sample Design
This section describes the sample design. It includes a description of the sampling frame, target sample size, stratification variables and sampling method. The sampling design employed is a stratified random sample of CWSs. The strata employed in the design are discussed in Section B.2.b.iii. Neyman allocation is used to efficiently allocate the sample of water systems among the strata.
B.2.b.i	Sampling Frame
The sampling frame is developed from SDWIS. SDWIS is a centralized database for information on PWSs, including their compliance with monitoring requirements, maximum contaminant levels (MCLs) and other requirements of the SDWA. The following information will be extracted from SDWIS for the statistical survey and verified by participating states:
   * Name of system.
   * Contact person.
   * Address of system.
   * Population served.
   * Total design capacity.
   * Number of connections.
   * Primary source (surface water or ground water).
   * PWS identification number (PWSID).
   * Ownership type.
   * Whether the water system purchases/sells water from/to another water system.
From these data, EPA will develop the frame from which EPA will calculate summary statistics (e.g., number of systems per state in pre-defined strata) for use in calculating sample size. For the modified panel approach, the 2015 sampling design will use the 2011 DWINSA sample and make targeted modifications to account for changes in the inventory of systems between 2011 and 2015. Systems that have closed since the 2011 DWINSA will be removed from the 2015 survey. The needs of merged systems will remain in the survey as the need of the combined system. New systems added to the inventory (i.e., systems that served 3,300 or fewer people in 2011 that now serve more than 3,300 people, or newly created systems) will be sampled to ensure the sample is representative of systems in 2015. New large systems (those serving more than 100,000 persons) will also be added to the census.
Justification for the Use of SDWIS
The following criteria are often used in assessing a proposed sampling frame:
   * It fully covers the target population.
   * It contains no duplication.
   * It contains no foreign elements (i.e., elements that are not members of the population).
   * It contains information for identifying and contacting the units selected in the sample.
   * It contains other information that will improve the efficiency of the sample design.
The units of observation for this survey are CWSs, a subset of PWSs. SDWIS is the ideal choice for a sample frame because of its inclusive coverage of all units of observation for the 2015 DWINSA. In addition, SDWIS has two other advantages: it contains information that will facilitate contacting the respondents and it contains other information that is useful in stratifying the sample, thereby improving the efficiency of the sample design.
In previous surveys where SDWIS was used as a sample frame, there have been criticisms of its utility. Since 1989, EPA has conducted audits of the quality of SDWIS data. As a result, EPA is aware of the problems with SDWIS. The audits, however, show that errors in classification of systems by strata proposed for the 2015 DWINSA are rare. The audits show that systems are misclassified by population or source in less than one percent of all cases.
To mitigate any potential problems with the sample frame, the 2015 DWINSA design anticipates substantial state involvement in the 2015 DWINSA process. For example, states will be checking the sample frame of systems that will be used to determine the final sample. In EPA's experience, states often have in-house data systems with very accurate data. Even if these data are not transmitted to SDWIS, they are available and can be used by states to check the sample frame.
B.2.b.ii	Sample Size
Exhibit B-2-1 at the end of this subsection shows the preliminary sample sizes for the 2015 DWINSA. For the modified panel approach, sample sizes for the 2015 DWINSA will be the same as for the 2011 DWINSA except for changes to accommodate: (1) the addition of large systems serving more than 100,000 people since the 2011 survey; (2) any partially surveyed states from the 2011 survey that fully participate in the 2015 survey; and (3) changes in the inventory of medium systems, including systems changing size or source categories or the creation of new systems. As shown on Exhibit B-2-1, the sampling design will be implemented to achieve state-level precision targets for CWSs serving more than 3,300 persons. Precision targets are discussed in Section B.2.c.
The task of determining the sample size for each stratum requires two steps. The first step determines the sample size for each state that achieves the precision targets for that state. The second step allocates the sample among the relevant strata in the state. The strata are described in section B.2.b.iii.
The first step calculates the total number of systems required at the state level to meet the precision requirements. The sample size is given by:

Where:
n0g = the sample size for state g (prior to the finite population correction)
Ngh = the total number of systems in the g[th] state in the h[th] stratum (taken from SDWIS)
sgh = the standard deviation of the variable of interest in the g[th] state for the h[th] stratum (estimated using data from the data from previous assessments)
H = the number of strata defined in the sample design for the g[th] state
Vg = the desired sampling variance for the total system (those serving more than 3,300 persons) capital needs estimate for state g.
The desired error in the sample is expressed as a relative error. In the above equation, Vg = (d/Zα * )[2].  is an estimate of the total capital needs for a given state.  is computed for each state by calculating the mean total capital needs for stratum h (from the prior DWINSAs) and multiplying this mean by the actual number of systems in each stratum for that state (Ngh). Summing across strata provides an estimate of . d is the half-width of the desired confidence interval (0.10 for the Assessment). Zα is the value of a standard normal distribution for a confidence level of 1- α, (1.96 for the Assessment).
Because the number of water systems is known and finite, the following population correction is applied:

The second step allocates the total sample to each sampling stratum. EPA will randomly draw this number of samples from each of these strata. The Neyman allocation is used to determine the sample size for each stratum:

(Because systems serving populations more than 100,000 are to be sampled with certainty, H is the number of strata of systems serving 100,000 or fewer persons.)
In order to implement these sample size and sample allocation equations, EPA needs estimates for Vg, Ngh, sgh and mean total capital needs by stratum. Information on mean total capital needs by stratum and sgh were estimated using data from the prior DWINSAs.
Exhibit B-2-1 State Sample Sizes
                                     State
      Estimated Total Number Of Systems Serving More Than 3,300 Persons
       Estimated Sample Size For Systems Serving More Than 3,300 Persons
Alaska *
                                                                             17
                                                                              1
Alabama
                                                                            348
                                                                            131
Arkansas
                                                                            181
                                                                             83
American Samoa
                                                                              1
                                                                              1
Arizona
                                                                            130
                                                                             39
California
                                                                            688
                                                                            170
Colorado
                                                                            169
                                                                             61
Connecticut
                                                                             57
                                                                             36
District of Columbia
                                                                              1
                                                                              1
Delaware *
                                                                             30
                                                                              3
Florida
                                                                            387
                                                                            128
Georgia
                                                                            237
                                                                             66
Guam
                                                                              3
                                                                              3
Hawaii *
                                                                             30
                                                                              2
Iowa
                                                                            138
                                                                             53
Idaho *
                                                                             51
                                                                              1
Illinois
                                                                            460
                                                                             98
Indiana
                                                                            214
                                                                             82
Kansas
                                                                            117
                                                                             65
Kentucky
                                                                            259
                                                                            141
Louisiana
                                                                            231
                                                                             65
Massachusetts
                                                                            253
                                                                             73
Maryland
                                                                             59
                                                                             26
Maine
                                                                             35
                                                                             25
Michigan
                                                                            303
                                                                             63
Minnesota
                                                                            181
                                                                             91
Missouri
                                                                            216
                                                                            121
Northern Mariana Islands
                                                                              2
                                                                              2
Mississippi
                                                                            202
                                                                            105
Montana *
                                                                             35
                                                                              1
North Carolina
                                                                            280
                                                                             80
North Dakota *
                                                                             32
                                                                              0
Nebraska *
                                                                             43
                                                                              2
New Hampshire *
                                                                             39
                                                                              1
New Jersey
                                                                            242
                                                                             61
New Mexico *
                                                                             60
                                                                              1
Nevada
                                                                             35
                                                                             15
New York
                                                                            362
                                                                             50
Ohio
                                                                            320
                                                                             90
Oklahoma
                                                                            165
                                                                             86
Oregon
                                                                            116
                                                                             54
Pennsylvania
                                                                            349
                                                                             83
Puerto Rico
                                                                            118
                                                                             58
Rhode Island *
                                                                             28
                                                                              3
South Carolina *
                                                                            159
                                                                              9
South Dakota *
                                                                             45
                                                                              2
Tennessee
                                                                            288
                                                                            158
Texas
                                                                            987
                                                                            144
Utah
                                                                            109
                                                                             50
Virginia
                                                                            160
                                                                             56
Virgin Islands
                                                                              2
                                                                              2
Vermont *
                                                                             34
                                                                              0
Washington
                                                                            213
                                                                             58
Wisconsin
                                                                            181
                                                                             58
West Virginia *
                                                                            110
                                                                              1
Wyoming *
                                                                             27
                                                                              0
Total
                                                                          9,539
                                                                          2,859
*Fifteen states are expected to opt out of participating in the statistical portion of the survey (i.e., collecting data from systems serving 3,301 to 100,000 persons). However, those states that have systems that serve more than 100,000 people will participate in the census portion of the survey (i.e., collecting data from systems serving more than 100,000 persons). For those 15 states, the number in the "Estimated Sample Size for Systems Serving More Than 3,300 Persons" represents the total number of systems in the state that serve more than 100,000 persons.

B.2.b.iii	 Stratification Variables
The objective of stratification is to increase the efficiency of the sampling design (thereby reducing the number of systems to be sampled for a given level of precision). Stratified sampling may produce a gain in precision in the estimates of the characteristics of the target population as compared to simple random sampling. In stratified sampling, the target population (i.e., CWSs) is divided into non-overlapping strata that are internally homogeneous, in that the measurements vary little from one unit to another (i.e., the within-stratum variance is minimized). If the within-stratum variance is relatively small, then a precise estimate of the variable of interest can be obtained with relatively small samples. Each of the strata estimates can be combined to obtain a precise estimate for the overall target population.
EPA's drinking water programs have historically evaluated CWSs based on (1) the number of persons served and (2) the primary water source (ground water and surface water). Using total capital need information obtained from prior DWINSAs, EPA evaluated several classification schemes. This analysis showed that the stratification scheme used in prior assessments (10 strata based on size and source) would be appropriate for the 2015 DWINSA. For some states, EPA may combine the 10,001to 25,000 and 25,001 to 50,000 size categories within each source category, resulting in 8 rather than 10 strata. EPA will combine these two size categories only if the sample using 8 strata is more efficient than the sample using 10 strata. The proposed strata for systems serving more than 3,300 persons are as follows:
                           Size of Population Served
                                    Source
                             Sample Methodologies
3,301  -  10,000
Ground
Panel approach with 25 percent refresh using a random sample.
3,301  -  10,000
Surface

10,001  -  25,000
Ground
Panel approach with 25 percent refresh using a random sample. In some states the number of strata will be reduced based on analysis of optimal stratum boundaries. Specifically, in some states systems serving between 10,001 and 50,000 will be in one size group rather than two.
10,001  -  25,000
Surface

25,001  -  50,000
Ground

25,001  -  50,000
Surface

50,001  -  100,000
Ground
Panel approach with 25 percent refresh using a random sample
50,001  -  100,000
Surface

More than 100,000
Ground
Sampled with certainty
More than 100,000
Surface

B.2.b.iv	 Sampling Method
As indicated above, all CWSs serving populations of more than 100,000 will be sampled with certainty.
For systems serving 3,301 to 100,000 persons, all CWSs will be allocated to eight strata, based on the population served and primary water source. The sample size for each stratum in each state will be determined by the sampling strategy outlined above. As previously described, the modified panel approach that will be used for the 2015 sample will begin with the 2011 DWINSA sample and make targeted modifications to account for changes in the sample between 2011 and 2015. EPA will then "refresh" the sample by randomly replacing 25 percent of the 2011 sample of systems serving 3,301 to 100,000 people with systems that were not included in the 2011 Assessment. To refresh the sample, 25 percent of systems serving 3,301 to 100,000 persons will be dropped from the survey and returned to the pool of systems that were not selected in 2011. The "refresh" will then randomly select systems from among the pool of systems that were not in the 2011 sample, the systems that were randomly dropped and new systems so that the number of systems in the sample reaches the same size as the 2011 sample.
The sampling method for the 25 percent refresh will be similar to the approach used in the 2011 survey. An equal probability random sample will be drawn from each stratum. Anticipating a level of non-response, EPA will over-sample the refresh systems to achieve the desired number of completed data collection instruments. Since the expected response rate for systems serving 3,301 to 100,000 persons is approximately 90 percent, EPA has increased the sample by approximately 10 percent. However, as discussed below, the DWINSA has consistently achieved a higher response rate than estimated. Therefore EPA has included the full sample size estimate in the burden estimate of this ICR.
B.2.c	Precision Requirements
B.2.c.i	Precision Targets
The sampling design for the 2015 DWINSA will be implemented at the state level. EPA's goal is to be 95 percent confident that the margin of error, when estimating the total capital needs facing these systems in each state, will be plus or minus 10 percent of the total need for these systems. For example, if the total need for these systems in a state is estimated to be $2 billion, EPA will be 95 percent confident that the actual total need is between $1.8 billion and $2.2 billion.
B.2.c.ii	Nonsampling Error
EPA has developed an assessment approach that will employ several quality assurance techniques to maximize response rates, response accuracy and processing accuracy to minimize non-sampling error.
Particular emphasis will be placed on maximizing response rates. Standard methods that have proved effective in other surveys involving states and water systems will be used, including the following:
   * EPA and the states will coordinate in the production of a cover letter for the 2015 DWINSA. EPA's opinion (shared by state drinking water administrators and trade associations) is that surveys on state letterhead will be better received than surveys on EPA letterhead. Therefore, states can use state-level cover letters signed by a senior state official instead of the EPA letter.
   * The states will place a telephone call to each participating system to ensure that they understand the survey process and their role.
   * The data collection instrument design, content and format were reviewed by states that participated in the 1995, 1999, 2003, 2007 and 2011 DWINSAs.
   * Questions being asked are those that owners or operators of systems should know. EPA does not ask questions that require monitoring, research or calculations on the part of the respondent.
   * The data collection instrument design is limited to a cover page of system information and characteristics and one project table, with three optional tables to record general information about the system's infrastructure inventory. By limiting the information requested, EPA believes that the average water system respondent can complete the data collection instrument in approximately 5.53 hours. Exhibit A-6-6 shows the breakdown of the total burden hours for CWSs by system size in the 2015 DWINSA.
   * Respondents will be encouraged to call state personnel who will be trained to answer questions. In addition, EPA will provide technical assistance to states and water systems.
   * The electronic format of the survey will make returning the data collection instrument convenient.
Standard methods to reduce other sources of non-sampling error also will be used:
   * EPA expects complete coverage of the target population using SDWIS, supplemented by state review of all systems.
   * Data will be 100 percent independently keyed and verified.
   * The data collection instrument is pre-coded to improve accuracy by eliminating unnecessary processing steps.
Supplementing these standard methods, EPA proposes several unique steps to eliminate non-sampling error which have been developed in concert with organizations representing the states and water systems. These organizations believe that the 2015 DWINSA is important and that a high level of participation by all water systems is essential to its success. Because of the substantial commitment being made by states and water systems to the 2015 DWINSA, EPA believes that response rates will be higher than most surveys of similar respondents. To ensure success, states and organizations representing water systems are taking the following steps.
 Participation of the states. Because the 2015 DWINSA will be used to allocate DWSRF funds to states, each entity has a strong interest in achieving a high response rate. EPA believes that their participation will be a key factor in guaranteeing high response rates and low item non-response. Personnel who work with water systems every day are in a strong position to encourage systems to complete the 2015 DWINSA form. States have committed to assisting EPA in achieving a high response rate by participating in follow-up activities. EPA will provide technical assistance to any system that has questions about the 2015 DWINSA.
 Participation of Organizations Representing Water Systems. EPA anticipates public support of organizations representing water systems. The prior assessments were supported by groups such as the American Water Works Association (AWWA), the National Association of Water Companies (NAWC) and the Association of Metropolitan Water Agencies (AMWA).
      This support by the organizations representing the respondents for the 2015 DWINSA can be helpful in many ways to minimize non-sampling errors. For example,
 In past DWINSAs, national water associations sent letters to each system in their membership, stressing the importance of surveying drinking water infrastructure needs. These letters, along with the letter from the states, helped convince water systems to respond. EPA will seek similar support from these associations for the 2015 DWINSA effort to encourage systems to complete the data collection instrument.
 In the past DWINSAs, the largest association representing water systems serving populations greater than 3,300, AWWA, provided support through its national organization. To improve the response rate, AWWA enlisted the support of its state affiliates to conduct telephone follow-up calls to encourage response. AWWA assisted in past DWINSAs to help achieve high response rates. EPA will seek similar support from AWWA in support of the 2015 DWINSA.
 Communications Strategy. EPA has developed a comprehensive communications strategy that will inform likely respondents of the need for their participation. This strategy includes articles in magazines, newsletters and bulletins of all major organizations that represent (or communicate with) water systems. This includes publications of all of the organizations mentioned above, plus the state and local affiliates of these organizations. The strategy is designed to develop widespread peer-group support for participation in the 2015 DWINSA.
B.2.d	Data Collection Instrument Design
Questions about system characteristics (name, population served, number of connections and other customary business information) will be pre-populated on all data collection instruments. The respondent needs only to enter accurate information if any pre-populated information is not correct.
The 2015 DWINSA is based on a matrix project table that requests a list of capital water system infrastructure projects that the system plans for the period 2015 through 2034. For each project listed, the water system is asked to provide:
   * Type of need.
   * Reason for need.
   * Documentation of need.
   * If the project is for new infrastructure or to replace, rehabilitate or expand existing infrastructure.
   * If the project is needed now to protect public health or if it is needed over the next 20 years to continue to provide safe drinking water.
   * The federal regulation or state requirement if the project is needed to meet a current federal regulation or state requirement.
   * Design capacity of source, storage and treatment projects.
   * Length and diameter of pipe projects.
   * Diameter for projects such as meters.
   * Cost of the project (if available).
   * Date of the cost estimate (if necessary).
   * Documentation of cost (if necessary).
For most of these variables, respondents will choose the appropriate "documentation," "type of need," "reason for need," or "regulation or requirement" from EPA's "Lists of Codes" (Appendix B). The data collection instrument has been designed to be concise, to avoid jargon and to avoid ambiguous words or instructions. Terms and formats have been standardized to the extent possible. There is no intentional bias in the ordering of the items.
B.3	PRE-TESTS AND PILOT TEST
B.3.a	Pre-tests
For the 2007 DWINSA the data collection instrument and some policies were modified substantially. EPA conducted two pre-tests of the data collection instrument for the 2007 DWINSA. These pre-tests were conducted by EPA's contractor, The Cadmus Group, Inc. The pre-tests gathered feedback on the effectiveness of the data collection instrument; highlighted imprecise, ambiguous or redundant questions; and indicated where further inquiry was needed. A pre-test was held in both Maine (four participants) and Montana (three participants). These states were chosen because they were both partially surveyed states and therefore most of their systems did not participate in the 2007 DWINSA. Also, the contractor conducting the pre-tests has offices in both these states and by conducting the pre-test in these states was able to reduce costs. The names of the seven systems were provided to EPA by the 2007 DWINSA state contacts. Based on the comments received, EPA made modifications to the data collection instrument. Since EPA's pre-tests of the 2007 DWINSA data collection instrument were so extensive, and because few changes have been made to the data collection instrument since the 2007 DWINSA, EPA believes that a pre-test is not needed for the 2015 DWINSA.
The data collection instrument was further modified for the 2011 DWINSA by the addition of questions and codes to gather information on projects with "green" and climate readiness attributes. Consequently, EPA conducted a limited peer review focused on these new questions. EPA did not conduct a pre-test of the 2011 DWINSA data collection instrument. Based on the limited number of states that submitted projects with "green" or climate readiness attributes indicated in the 2011 effort, EPA concluded these attributes were likely underreported.   For the 2015 DWINSA, the "green" and climate readiness questions will be removed from the data collection instrument. Instead, EPA will explore streamlined approaches that might enable the Agency, during the Survey review process, to identify and flag projects that are likely to have "green," climate readiness or climate resilience attributes.
B.3.b	Pilot Test
To eliminate unnecessary burden on states and water systems, it has been decided that no pilot test for the 2015 DWINSA will be conducted. A pilot test was conducted for the 1995 DWINSA and consisted of 60 CWSs from New York and Texas.
One change for the 2015 DWINSA is that EPA will deliver all data collection instruments electronically rather than mailing hard copies, as was done for the 1995, 1999, 2003, 2007 and 2011 DWINSAs. Several states received and used electronic data collection instruments in the 2011 DWINSA and states attending the May 2014 workgroup meeting expressed no concerns about using the electronic format. EPA therefore believes this approach has been well tested and has proven to be successful; therefore, it is not necessary to repeat this testing step.
B.4	COLLECTION METHODS AND FOLLOW-UP
B.4.a	Collection Method
The proposed collection method is an electronic survey. The data collection instrument including the Lists of Codes will be sent to the states via e-mail. State drinking water agencies will provide the data collection instrument (with the project table prepopulated for systems that participated in 2011 and blank for those that did not) and other necessary documents to the systems in the sample. They will follow-up if the data collection instrument has not been returned in 30 days. For a complete description of the follow-up procedures proposed to increase the response rate, see section B.2.c.ii.
B.4.b	Survey Response and Follow-up
The target response rate (defined as the ratio of responses to eligible respondents) for the 2015 DWINSA is 90 percent. EPA realizes that this is an ambitious target, but EPA believes that there are special circumstances that warrant such a target. Also, overall response rates of 94, 97, 96, 93 and 97 percent were achieved in the 1995, 1999, 2003, 2007 and 2011 surveys, respectively. In the first five surveys, EPA conducted the following activities to achieve that high response rate.
 Seek Support from the Respondent Population. This is a national survey of infrastructure needs for drinking water systems. EPA will work to bring to the attention of water systems, as well as all national organizations representing these systems, the importance of the DWINSA results. As with the previous five surveys, all national organizations will be contacted by EPA to seek their endorsement of the DWINSA and to communicate to their members the importance of a high response rate to their members. As discussed in Section B.2.c, in past surveys, organizations have provided access to their newsletters and magazines to publicize and endorse participation in the DWINSA. For the 2015 Survey, EPA will seek similar efforts by these organizations.
 Follow-up by States and Respondent Peer Groups. Since a majority of states have indicated their willingness to participate in follow-up activities, EPA has requested that state personnel, most of whom are personally familiar with the respondents, conduct follow-up procedures including the use of reminder letters and telephone calls to systems that have not responded with the needed information or documentation. If the follow-up fails after three attempts (one reminder letter plus two telephone follow-up calls), EPA is planning to shift to a second approach of peer-group follow-up by members of a trade association, such as AWWA.

B.5	ANALYZING AND REPORTING SURVEY RESULTS
B.5.a	Data Preparation
State personnel will check all cost data and documentation to ensure that it is consistent with state and national standards. States will then send the completed and reviewed data collection instruments to EPA for a second round of review by EPA contractor staff.
Once data have been checked, the contractor will key and verify the data. Senior data entry staff will be used for the verification process to improve quality control. Editing will include automated logic and range checks and checks for missing data. Missing cost data will be modeled, using other information provided by the respondents on the data collection instrument. When modeling is insufficient, missing data will be imputed using standard methods such as cell means and regression. The sample of water systems will be weighted so that stratum estimates can be summed to prepare state-level estimates for the 2015 DWINSA.
B.5.b	Analysis
EPA will prepare a report that tabulates the results of the 2015 DWINSA and explains the precision of the estimates of total capital needs. Examples of statistics that will be produced include:
 Total capital needs by state and by types of need.
 Total capital needs by domains within the total population, e.g., systems serving populations greater than 100,000.
 Standard errors calculated for key statistics.
The analysis will be similar to that of previous DWINSAs.
B.5.c	Reporting Results
The 2015 DWINSA results will be made available to EPA and the public through:
 A printed report that is submitted to Congress on drinking water infrastructure needs. This report will be made available to all participants in the 2015 DWINSA and the public through EPA's Safe Drinking Water website.
 Desktop computer access to state data on the DWINSA Web site without modeled project costs (each state can access only its own data).
 Desktop computer access to the entire data system (EPA only).
A report providing the cost models used to develop costs for the 2015 DWINSA will be made available to EPA and the public through EPA's Safe Drinking Water Web site.

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Appendix A  -  Public Notice Required Prior to ICR Submission to OMB
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Appendix B  -  Data Collection Instrument and Lists of Codes

\s
    Instructions for Each Column on the 2015 Drinking Water Infrastructure
                   Needs Survey and Assessment Questionnaire
Column Title
Instructions
Project Number
Number the projects in each category in sequence, using the following range of numbers for each category of need:
 - 1000's Source, treatment, storage, and pumping projects
 - 2000's Transmission and distribution projects
 - 3000's Meters, service lines, backflow prevention, valves, etc.
Project Name
Provide a name that briefly describes and identifies the project.
Type of Need
Refer to List 1 in the Lists of Codes and enter the code(s) that best identifies the project. More than one code may apply to a project if a cost is provided. Use only one code if no cost is available. Codes not applicable to the 2015 DWINSA but that may appear in 2011 DWINSA data are shown in List 1 in italics and with strike-through to indicate they should not be used.
Reason for Need
Refer to List 2 in the Lists of Codes and enter the code(s) that best justifies the project. More than one code may apply to a project.
New,
Replace, Expand/Upgrade,
or
ReHabilitate
Identify whether the project is for:
 - New infrastructure installation where none exists, enter `N'
  		Resulting infrastructure is entirely new.
 - Replacement of existing infrastructure, enter `R'
 		Existing infrastructure is replaced with similar infrastructure.
 - Expansion/Upgrade of a complete treatment plant, enter `E'
 	Major improvements to an existing complete plant that adds or changes unit processes or results in an increase in capacity. Only use for complete treatment plants.
 - Rehabilitation of existing infrastructure, enter `H'
 	Restore existing infrastructure to near-new condition.
Current or Future
Identify whether the project is:
- Needed now, enter `C'
	 (even if you cannot start construction now)
- Not needed now, enter `F'
	(but will be necessary before 12/31/2034)
Regulation or Secondary Purpose
If the project is needed to maintain or obtain compliance with a regulation, secondary MCL, or state requirement, refer to List 3 in the Lists of Codes and enter the appropriate code. Enter `4A' if no code applies.
Design Capacity
Enter the design capacity when applicable:
 - million gallons per day (MGD) for source, treatment, and pumping;
 - million gallons (MG) for storage;
 - kilowatts (kW) for emergency power.
For this survey, "design capacity" is the total volume or the flow that can be produced when all components of the project are operating (e.g., for disinfection, record the volume of water treated in MGD).

Column Title
Instructions
Diameter
Enter the diameter (in inches, using decimals) if the project is for pipe, valves, backflow prevention, or meters. Use a separate project number and line for different sizes of infrastructure if a documented cost is not available. Diameter is not needed for service lines.
Length
Enter the length of pipe (in feet) that must be rehabilitated, replaced, or installed as new. Use a separate project number and line for different sizes of pipe if a documented cost is not available.
Number Needed
If you have multiple identical projects at the same capacity or multiple identical items, indicate the total number needed (e.g., rehabilitate 10 wells each with a 0.5 MGD capacity, or replace 1,000 0.625-inch meters).
If you use this column and provide a project cost, the cost should reflect the entire project (i.e., all 10 wells or all 1,000 meters, not the cost of an individual well or meter).
Cost Estimate
If an existing cost estimate is available, enter the documented cost estimate for this project. Do not use cost estimates that were prepared prior to January 1, 2005. If no cost estimate is provided and modeling parameters are recorded, EPA will use models to estimate the cost. Do not develop a cost estimate for this survey.
Cost Date
If a documented cost estimate is provided, enter the month and year (MM/YYYY) of the cost estimate. EPA will adjust costs to current-year dollars.
Documentation
Refer to List 4 in the Lists of Codes and enter the code(s) that applies to the type of documentation provided that explains why the project is needed. If a cost estimate is provided, also enter the code that applies to the type of cost documentation. More than one code may apply to a project.
Remove, Modify, or Validate
This column appears for systems that participated in the 2011 DWINSA. An asterisk (*) indicates the project must be removed, modified, or have a project-specific validation for the 2015 DWINSA.

                               Important Notes:
     o  What is a "need"? Installation or rehabilitation of capital infrastructure needed over the next 20 years to obtain or maintain service to existing customers or to existing homes with inadequate or unsafe water that are not currently connected. Projects substantially for meeting anticipated future population growth or for fire flow are not allowed for the DWINSA.
     o  What is "independent documentation"? Documents generated through a process independent of the DWINSA (e.g., CIP, master plan, sanitary survey report).
     o  What is "survey-generated documentation"? Documents generated specifically for the survey that are written by the system or the state.
Please use the Documentation Summary tab of the Questionnaire to provide survey-generated documentation of need and/or provide information on the independent documentation for the project. A description of each project or a copy of the documentation must be provided and be clearly identified by project number.

Important Notes:
     o  What is a "need"? Installation or rehabilitation of capital infrastructure needed over the next 20 years to obtain or maintain service to existing customers or to existing homes with inadequate or unsafe water that are not currently connected. Projects substantially for meeting anticipated future population growth or for fire flow are not allowed for the DWINSA.
     o  What is "independent documentation"? Documents generated through a process independent of the DWINSA (e.g., CIP, master plan, sanitary survey report).
     o  What is "survey-generated documentation"? Documents generated specifically for the survey that are written by the system or the state.
Please use the Documentation Summary tab of the Questionnaire to provide survey-generated documentation of need and/or provide information on the independent documentation for the project. A description of each project or a copy of the documentation must be provided and be clearly identified by project number.

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                             LIST 1 - TYPE OF NEED
Code
Type of Need
RAW/UNTREATED WATER SOURCE
R1
Well (including pump and appurtenances)
R2
Well Pump
R3
Well House [1]
R4
Eliminate Well Pit 1
R5
Abandon Well [1]
R6
Aquifer Storage and Recovery Well
R7
Surface Water Intake
R8
Raw Water Pump
R9
Off-Stream Raw Water Storage [2]
R10
Spring
R11
Destratification [1]
TREATMENT: Disinfection
T1
Chlorination
T2
Chloramination
T3
Chlorine Dioxide
T4
Ozonation
T5
Mixed Oxidant Type Equipment
T6
Ultraviolet Disinfection
T7
Contact Basin for CT
T8
Dechlorination of Treated Water
T9
Chlorine Gas Scrubber
TREATMENT: Complete Plants (N/R/E require independent documentation)
T10
Conventional Filter Plant (includes CAC technologies)
T11
Direct or In-line Filter Plant
T12
Slow Sand Filter Plant
T13
Diatomaceous Earth Filter Plant
T14
Membrane Technology for Particulate Removal
T15
Cartridge or Bag Filtration Plant
T16
Lime Softening
T17
Reverse Osmosis
T18
Electrodialysis
T19
Activated Alumina
T20
Manganese Green Sand (or other oxidation/filtration technology)
T21
Ion Exchange
T22
Groundwater Chemical-feed
T23
Iron Adsorption
T24
Aeration
TREATMENT: Other Components / Equipment / Processes
T30
Zebra Mussel Control
T31
Corrosion Control (chemical addition)
T32
Powdered Activated Carbon
T33
Aeration (component)
T34
Sequestering for Iron and/or Manganese
1 These codes are not applicable to the 2015 DWINSA but may appear in 2011 DWINSA data.
2 Cost must be provided; cost of this infrastructure cannot be modeled.

1 These codes are not applicable to the 2015 DWINSA but may appear in 2011 DWINSA data.
2 Cost must be provided; cost of this infrastructure cannot be modeled.

                         LIST 1 - TYPE OF NEED (cont.)
Code
Type of Need
TREATMENT: Other Components / Equipment / Processes
T35
Chemical Feed
T36
Chemical Storage Tank
T37
Fluoride Addition
T38
Presedimentation Basin
T39
Sedimentation/Flocculation
T40
Granular Activated Carbon
T41
Membrane Filtration (not complete plant)
T42
Media Filters
T43
Waste Handling/Treatment: Mechanical (not included in another project)
T44
Waste Handling/Treatment: Nonmechanical or Connection to a Sanitary Sewer
(not included in another project)
T45
Type of Treatment Unknown
T46
Other (Please include an explanation) 2
TRANSMISSION MAINS: (Any mains that transport raw water to the treatment plant, or treated water from the plant to the distribution system grid.)
X1
Raw Water Transmission
X2
Finished Water Transmission
DISTRIBUTION
M1
Distribution Mains (any mains that transport water through a piping grid serving customers; see "transmission" above)
M2
Lead (Pb) Service Line Replacement
M3
Service Lines (other than lead service lines)
M4
Hydrants 1
M5
Valves (gate, butterfly, etc.) (not included in a pipe project)
M6
Control Valves (PRVs, altitude, etc.)
M7
Backflow Prevention Devices/Assemblies
M8
Water Meters
FINISHED/TREATED WATER STORAGE
S1
Elevated Finished/Treated Water Storage
S2
Ground-level Finished/Treated Water Storage
S3
Hydropneumatic Storage
S5
Cover for Existing Finished/Treated Water Storage
PUMP STATION AND FINISHED WATER PUMP
P1
Finished Water Pump
P2
Pump Station (booster or raw water pump station-may include clearwell, pumps, housing)
OTHER INFRASTRUCTURE NEEDS
W1
Laboratory Capital Costs for Labs Owned by the System [1]
W2
Computer and Automation Costs (SCADA)
W3
Pump Controls/Telemetry [1]
W4
Emergency Power (enter design capacity as kilowatts)
W5-W9
Fencing and Security-related needs 1
W10
Other (Please include an explanation) 2

                           LIST 2 - REASON FOR NEED

Code
Reason the Project is Needed
A1
Project is for existing infrastructure that is or will be old or deteriorated by 12/31/2034.
A2
Project is to correct a deficiency in source water quantity caused by current user demand.
A3
Project is to correct a deficiency in storage capacity caused by current user demand.
A4
Project is to correct existing pressure problems (not related to fire flow).
A5
Project needed as a result of, but not in preparation for, a natural disaster.
A6
Project is to obtain or maintain compliance with an existing regulation (enter the regulation code from List 3 in the Lists of Codes in the regulation column of the questionnaire).
A7
Project is to obtain or maintain compliance with a secondary standard (e.g., iron, taste and odor, and color) (enter regulation code 2A in the regulation column of the questionnaire).
A8
Project is for consolidation with and/or connection to an existing public water system.
A9
Project is for extending service to existing homes without adequate water quantity or quality.
A10
[A10 is not applicable to the 2015 DWINSA but may appear in 2011 DWINSA data. A10 referred to security-related needs]
A11
Use this code if codes A1-A9 do not apply.

                   LIST 3 - REGULATION OR SECONDARY PURPOSE

Code
Regulation or Secondary Purpose
EXISTING SDWA REGULATIONS
1A
Surface Water Treatment Regulations (Surface Water Treatment Rule, Interim Enhanced Surface Water Treatment Rule, Filter Backwash Recycling Rule, Long Term 1 Enhanced Surface Water Treatment Rule, or Long Term 2 Enhanced Surface Water Treatment Rule)
1B
Total Coliform Rule or Revised Total Coliform Rule
1C
Nitrate or Nitrite Standard
1D
Lead and Copper Rule
1E
Arsenic Rule
1F
Stage 1 or Stage 2 Disinfectants/Disinfection Byproducts Rules
1G
Other Regulated VOCs, SOCs, IOCs, or Radionuclides (excludes Radon)
1H
Ground Water Rule
OTHER
2A
Secondary Contaminants (e.g., iron, taste and odor, or color)
2B
State Requirements
IF NONE OF THE ABOVE CODES APPLY
4A
Use this code if none of the codes above apply
PROPOSED AND RECENTLY PROMULGATED SDWA REGULATIONS
Needs associated solely with the Proposed Radon Rule are not allowable and should not be included. The costs for these needs, estimated for the rule's Economic Analysis, will be added to the total national need.
As of January 1, 2015, there were no other proposed rules or recently promulgated rules applicable to the 2015 DWINSA.

                            LIST 4 - DOCUMENTATION
Code
Independent Documentation of Need and/or Cost
1
Capital Improvement Plan or Master Plan. The plan must address why the project is needed and/or provide a cost.
2
Facilities Plan or Preliminary Engineering Report. Excerpts justifying need and/or cost from the plan or report are acceptable if project-specific.
3
Grant or Loan Application Form. An application form is acceptable if it specifically describes a problem requiring capital expenditures.
4
Engineer's Estimate or Bid Tabulation. These must be project specific and independently generated. They must also be accompanied by an explanation of why the project is needed.
Code
Independent Documentation of Need Only
5
Intended Use Plan/State Priority List. The excerpts must include a description of why the project is needed. Costs from IUPs will not be used - modeling parameters or other cost documentation must be provided.
6
Comprehensive Performance Evaluation (CPE) or Sanitary Survey Results. The results or recommendations may be used to justify need if the state concurs.
7
Monitoring Results. Monitoring results indicating an MCL exceedance or a trending toward an exceedance can demonstrate a need for a project if accompanied by a written statement explaining how the results demonstrate the need.
8
Other Independent Document. Use this code if documentation is independent but none of the codes listed above apply. Examples include: state enforcement order/notice of violation, engineering studies, water main break report, repair reports, and distribution system studies.
Code
Independent Documentation of Cost Only

9

Cost of Previous Comparable Construction. This may be used to justify costs if the costs are project-specific. It must include documentation of how the costs were derived.
Code
Survey-generated Documentation of Need Only
10
Written by State. Brief description and statement of need written by the state.
11
Written by System. Brief description and statement of need written by the system.
Code
Documentation Submitted for Previous DWINSA
20
Project Relied on 2007 DWINSA Documentation. Code not applicable to the 2015 DWINSA. Resubmit documentation if it is needed.
21
Project Relies on 2011 DWINSA Documentation. Submit project-specific validation statement. Other documentation codes also apply if additional documentation is submitted for the 2015 DWINSA.

Appendix C  -  Comments and Response to Comments Received on the 2015 DWINSA Peer Review

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Introduction to the 2015 DWINSA Peer Review Comment and Response
EPA has assessed the drinking water infrastructure needs of public water supplies through a national survey of drinking water systems every four years since 1995. Using a stratified random statistical sample of water systems, the Agency assesses need by evaluating project-level data from each system sampled including information about the type of project, its size or capacity, and its cost. A new sample was selected for each Assessment and the same basic approach (with some notable exceptions) was used in 1995, 1999, 2003, 2007 and 2011.
EPA proposes using a different statistical approach for the design of the 2015 Drinking Water Infrastructure Needs Survey and Assessment (DWINSA or Assessment). Rather than select a completely new sample of systems in 2015, EPA proposes to survey the participants in the 2011 Assessment and re-assess their 20-year investment need in 2015. By using information from the 2011 review as a starting point, this panel approach would reduce the amount of time required to review each system's response and would allow for analyses of trends. The sample will be "refreshed" by randomly selecting up to 25 percent of the 2011 sample in each stratum to be dropped and placed back in the pool of systems that were not selected in 2011. Systems will then randomly be selected from among the pool of systems that were not in the 2011 sample and the systems that were dropped.
The proposed panel (or longitudinal) approach, which tracks a cross-section of observations over time, is common in econometric studies and is used to study individuals, households, firms and utilities. It provides advantages in terms of costs while allowing for trend analyses and providing probability samples of systems on which estimates of each state's needs can be based.
EPA asked two statisticians to review the proposed approach. The peer review charge is to assess the proposed panel approach as outlined in the document: Proposed Panel Study Approach to the 2015 Drinking Water Infrastructure Needs Survey and Assessment. The approach was reviewed internally by Dennis Guignet, Ph.D., of EPA's National Center for Environmental Statistics. It also was reviewed by Don L. Stevens Jr., Ph.D., of Stevens Environmental Statistics. Each reviewer's comments and EPA's responses are provided below. The comments are presented without attribution by name to either reviewer.

Reviewer # 1
I. GENERAL IMPRESSIONS
The general approach of using a partial replacement panel study is eminently sensible for studies with dual objectives of estimating status and trends. Besides the potential cost savings of reducing the review cost, trend estimates can be more precise because of elimination of a component of variance.
There is no indication of plans to continue the panel approach beyond 2015. The full potential of a panel design can only be realized if it is kept in place for multiple surveys. The current plan should address this and also specify how the sample will be "refreshed" in subsequent years.
EPA response: EPA recognizes the longer-term potential offered by the panel approach and will evaluate its future use, including the use of the refresh, in conjunction with the completion of the 2015 Survey.
Neyman allocation is a reasonable approach, but some of the resulting sample sizes in the 2011 table seem a bit extreme. For example, New York was allocated a sample of 3 from 123 small ground water systems, but Nevada was allocated a sample of 3 from 4 small surface water systems. Was the variation really that extreme? While Neyman allocation is theoretically optimal, that's only the case if the real variance is known. In practice, the variance is always estimated, and hence has some uncertainty, especially variance based on small sample sizes. It appears as if "3" were set as a minimum sample size; if, so, I think that's too small.
      EPA response: The allocation of each state's sample by strata depends on the variance, the number of systems in each stratum and the share of the total need in the census strata (systems serving more than 100,000 persons). To determine the sample size needed per state and to allocate the sample among the strata, we must estimate the variance and total need for each state. We use data from prior Assessments to estimate the total need and variance. In both New York and Nevada, systems serving more than 100,000 account for more than 80 percent of total need, even though they comprise less than 10 percent of the systems.
      Because systems serving more than 100,000 persons account for such a large share of the total need, the Neyman allocation often requires very few systems -- 2, 1 or fewer -- per stratum. The sampling plan requires at least 3 systems per strata. (We need at least 2 systems per stratum to calculate the standard error and select 3 to allow for non-response.)
II. RESPONSE TO CHARGE QUESTIONS
1. Sampling Plan/Statistical Theory
a. Are there any general comments or noticeable flaws with the proposed panel study approach?
The proposal is to refresh 25% of the sample. Many sample sizes are small and not divisible by 4. The proposal should specify how the dropped sites are to be selected if, for example, the sample size is 7.
      EPA response: The study will round the number to be resampled to the nearest integer. If a stratum has seven systems in the sample we will resample two systems.
b. Is the proposed panel study approach complete?
It was not clear how actual needs data was to be collected for the states retained from the 2011 sample. Are the states asked to update their 2011 response? Accurate needs data is critical to the success of the panel approach. In the usual application of a panel study, the retained elements are re-measured along with the new elements. Point 4 in the "Proposed Survey Approach" seems to suggest that the process for new and retained systems will be different. This could be a serious problem unless the "rules" EPA has yet to develop in fact yield comparable needs data.
      EPA response: The systems retained from the 2011 survey will be asked to update their 2011 response. The guidelines ensure that only needs allowable under the Drinking Water State Revolving Fund (DWSRF) are included in the survey. These guidelines and the EPA's review of the systems' responses ensure they are consistent with prior surveys and with the new systems added to the survey.
c. Is the statistical theory the correct approach and does it give the desired results?
The statistical theory is correct. Depending on how the response for sites not replaced is determined, the estimates should be acceptable. However, because of constraints on refreshing 25% of a small sample, the desired cost savings may not be realized.
      EPA response: EPA recognizes that the 25% refresh will reduce the potential savings associated with the panel approach.
2. Will EPA's approach for the 2015 Assessment to "refresh 25% of the 2011 sample with new systems from the 2011 sample" adequately:
a. Represent system needs for 2015?
It depends on how the cost data for the non-replaced systems is determined. As I noted above, the proposal was not clear on that point. If the cost data is correct for 2015, then the system needs for 2015 should be adequately represented.
      EPA response: See above.
b. Address states concerns that their allotment is too closely tied to the 2011 Assessment and help alleviate a potential source of bias?
See my response above. I'm not sure what "potential source of bias" is present. Provided the needs data is correct for 2015, then the results are unbiased.
3. As part of the panel approach, EPA is planning on keeping the size of the sample of medium systems the same as in 2011. Should it adjust the sample size if necessary to meet the desired precision targets, or should it keep the sample size the same as in 2011?
The sample size should be adjusted to meet precision targets. The sample sizes were based on Neyman allocation, sometime with variance estimates based on very small samples. As more (better) information becomes available on variation, the sample allocation should certainly be reconsidered.
      EPA response: In 2011, the sample was designed to meet a precision target of plus or minus 10 percent of the total need for each state. Data from 2003 and 2007 were used to estimate the variance in order to calculate the required sample sizes. EPA will update its estimates of the variance using the data from the 2011 Assessment.
      The sample size needed in 2015 can change because of changes in the inventory or changes in the estimated variance of total need by state. In principal, the required sample size can increase or decrease due to these changes. The sample for some states may increase while others may decrease. The allocation among a state's strata may also change, even if the total sample required does not change.
      EPA will revise the sampling plan based on this comment. In cases where the sample size needed increases, EPA will drop 25 percent of the 2011 sample, returning the dropped systems to the pool of systems that can be sampled. EPA will then randomly select the number of additional systems required to meet the precision targets. For example, if the 2011 sample size was 12 and the 2015 sample size must increase to 15 to meet the precision target, EPA will first randomly select and drop 3 systems from the sample and will then randomly select 6 systems from the inventory of remaining systems. The three systems that were dropped may get sampled again.
      In cases where the required sample size decreases, EPA will randomly select systems to remove from the sample. It will then randomly select 25 percent of the remaining sample to drop and replace. EPA will then randomly select from the frame -- including systems that were dropped in the first two steps -- systems to replace the 25 percent dropped as part as the refresh.
III. SPECIFIC OBSERVATIONS
                                     Page
                                  Paragraph
                              Comment or Question
5
3
It is a mistake not to re-evaluate sample sizes based on revised variance estimates or frame changes.
EPA response: See response to 3, above.
6
b
P4, paragraph 4, suggests that the new systems would have a separate supplemental sample. This paragraph suggests that the new systems will be included in the frame for the replacement systems. Which is the case?
EPA response: We will clarify the language and revise P4 paragraph 4. Systems added to inventory will be included in the frame for the replacement systems and will have a chance of being selected as part of the refresh.
6
4
The "rules for how projects are included in the 2011 Assessment" are critical. If this is not done carefully, than the whole study could be compromised.
EPA response: EPA recognizes the importance of the rules that guide project review.

Reviewer # 2
In responding to the below charge questions, my review focuses on adapting the previously peer-reviewed 2011 sampling design to accommodate a panel data approach. Although I reviewed much of the 2011 sampling plan to gather background information, my comments below focus only on the proposed changes for the 2015 sampling plan.
1. Sampling Plan/Statistical Theory
a. Are there any general comments or noticeable flaws with the proposed panel study approach?
Overall, the proposed changes to the 2011 sampling plan to accommodate the collection of a panel dataset seem reasonable, and I find no major flaws based on my review. Statistical theory suggests that the stratified random sample of medium facilities chosen in 2011 was representative of facilities at that time. It stands to reason that this same sample is still representative of the population of medium systems in 2015.
Besides minor considerations discussed in my below responses, I think the proposed panel approach is valid and offers several advantages. In addition to the cited cost-savings and reduced burden to the EPA and Water Systems, a panel data approach increases EPA's ability to analytically assess the effectiveness of funds in completing projects, to examine how cost estimates for individual projects evolve over time and the initial accuracy of estimates derived by individual water systems or EPA, and to potentially distinguish between total costs projected over the next 20 years versus incremental costs relative to previous assessments.
      EPA response: Following completion of the 2015 DWINSA, we will be assessing these possible future benefits of the new approach in designing the 2019 effort.
b. Is the proposed panel study approach complete?
Yes, the proposed panel approach is complete. My only suggestion is that EPA establish their decision rules for "how projects included in the 2011 Assessment will be reviewed and how new projects will be handled" (pg 6), and that this be made clear beforehand. No details are currently provided with the proposed panel approach plan.
These decision rules are particularly important given that the requested fields (e.g., "project name") are open-ended, which could lead to slight differences in responses for the same project. Additionally, it is seems possible that the Water System and EPA staff who filled-out and reviewed the survey in 2011 may not be the same individuals in 2015.
Perhaps it would be worthwhile to send previous survey responses to systems along with the 2015 survey? If systems have their last list of projects in front of them, then this may minimize the potential for unwanted overlap and help encourage consistent project names, etc. across the two time periods in the panel. At the same time, this would be a systematic difference between the panel sample compared to the 2015 "refresh" sample, and so consideration should be given to any potential biases that could inadvertently triggered if the previous 2011 responses were provided. In any case, since the census of large systems is already a panel dataset, if such inconsistency issues were not an issue there, then perhaps the above concern is not warranted in the context of medium sized systems either.
      EPA response: EPA recognizes the importance of the rules for how projects are reviewed and how new projects will be handled. The systems retained from the 2011 survey will be asked to update their 2011 response. EPA will send systems that participated in the 2011 survey their responses to the survey as a starting point for the 2015 assessment. Guidelines will ensure that only needs allowable under the DWSRF are included in the survey. These guidelines and the EPA's review of the systems' responses ensure they are consistent with prior surveys and with the new systems added to the survey.
c. Is the statistical theory the correct approach and does it give the desired results?
Yes, the statistical theory appears correct. However, if the desired results are to estimate the 95% confidence of total need by state with a 10% level of precision, then this may not necessarily be obtained. Please see response to item 3.
      EPA response: EPA will adjust the size of the sample to allow for changes in the inventory of water systems as well as revisions to estimates of the variance in need. See the response to item 3, below.
2. Will EPA's approach for the 2015 Assessment to "refresh 25% of the 2011 sample with new systems from the 2011 sample" adequately:
a. Represent system needs for 2015?
Yes, the proposed panel approach should provide a representative sample of system needs for 2015, even absent the 25% sample refresher. The 25% refresher will further ensure a representative sample.
Statistical theory suggests that the stratified random sample of medium facilities chosen in 2011 was representative of facilities at that time. It stands to reason that this same sample is still representative of the population of medium systems in 2015. One potential flaw in this thought is if these stratified randomly selected facilities become inherently different from the population of other medium systems within their strata in between 2011 and 2015. For example, if a facility's particular needs systematically change as a result of previously filling out the survey, then the sample could be less representative of the population within that strata. If there is any reason to suspect that a facility's allocation of funds, effectiveness in spending funds, or even how they fill-out the survey, are systematically different due to the fact that that particular facility filled out a survey in 2011, or that they know they may fill out future surveys, then this could lead to potential biases in the 2015 sample.
However, no evidence was presented suggesting that this could be the case, and the introduction of a 25% sample "refresher" within each strata should alleviate concerns along these lines. Furthermore, by comparing the "refreshed" sample to the sample of systems included in both the 2011 and 2015 sample, one can statistically test whether such facilities are similar (e.g., t-tests of mean responses across subsamples). Although, such tests likely require the pooling of systems across strata in order to achieve the desired level of statistical power, such comparisons may still be insightful. With the appropriate caveats such comparisons could shed light onto the validity of the panel approach and the need (or lack of a need) for a sample "refresher" in future surveys beyond 2015.
      EPA response: EPA recognizes the potential bias that can be introduced by asking systems to report their project need again. Systems may have learned from their experience in the 2011 Assessment and change their estimate of their future needs as a result. This potential source of bias is not new as systems serving more than 100,000 have participated in every survey since the initial assessment in 1995. There is no evidence that large systems' responses have been affected by their long-term participation in the survey. Furthermore, many medium systems have been included in more than one Assessment and their responses generally appear to be consistent with medium systems of similar size and type that have not been included in more than one Assessment.
b. Address states concerns that their allotment is too closely tied to the 2011 Assessment and help alleviate a potential source of bias?
I was not provided with any documentation of the States' comments or concerns, but I presume that such concerns stem from the fact that a "bad" draw of the random sample for a State could lead to concerns that the State's total allotment is too closely tied to the sample selected in 2011. If this is the case, then such concerns could be aggravated by the fact that this same sample would be used to assess their needs in 2015. That said, these samples are randomly drawn from within each strata. No matter when a sample is drawn (2011 or 2015), the States have a similar probability of getting a more or less "favorable" draw. Such discrepancies are random, and are an inherent component of any statistical sampling plan. This should not lead to any systematic biases, however, in estimating State needs.
All that said, since the 25% refresh is again a random selection of systems within each strata, this will help alleviate any potential concerns and perhaps even provide an opportunity to statistically test whether such concerns are warranted (see response to item 2a above).
      EPA response: EPA is implementing the 25 percent refresh in light of discussions with states and to address issues also noted by the reviewer.
3. As part of the panel approach, EPA is planning on keeping the size of the sample of medium systems the same as in 2011. Should it adjust the sample size if necessary to meet the desired precision targets, or should it keep the sample size the same as in 2011?
 On page 5 of the "Proposed Panel Study" document it states that "EPA will not change the sample sizes to account for revised estimates of the variance in system need or changes in the inventory of medium systems." Keeping the sample the same size each time period within a panel dataset may be an attractive feature, but if this is the preferred path some additional justification should be provided. If the desire is to continue to maintain a 10% level of precision then it seems that the sample size should be adjusted to account for changes in the size of the population of systems within the different strata, as well as the within strata variance.
For example, in instances where the population of facilities within a strata increases, based on equations 2.2 through 2.5 in Appendix 2 of the "Proposed Panel Study" document, it seems necessary to increase the sample size within the respective strata in order to maintain a 10% level of precision. I'm not arguing that the sample sizes should necessarily be changed in response to any changes in the number of systems in the population, but if the 2011 samples sizes were maintained in 2015, then this needs to be made transparent and the appropriate caveats should be included. Most notably, claims of 10% precision should not be made if that is not the level of precision obtained when keeping the sample size the same as that in 2011.
On a similar note, it appears that an optimum allocation design was used to determine the sample size and allocation across strata, which accounts for information obtained from previous surveys (i.e., estimated standard deviation within each strata and total state costs). On page 20 of the "Proposed Panel Study" document, it is stated that in determining the 2011 sample sizes, this information was estimated based on data from the 2003 Assessment; in other parts it states 2007. I presume this should always read as 2007, but if not then it is unclear why the 2007 Assessment was not used as this was the most recent data prior to the 2011 survey.
In any case, it seems that state cost and stratum standard deviation estimates can be obtained based on information obtained from the 2011 survey, which in turn would provide a more current determination of the sample size and allocation needed to obtain the desired precision targets. Perhaps doing so in a panel structure introduces some issues that I am not aware of, but this may be something worth considering in order to minimize survey costs and obtain the desired level of precision.
      EPA response: It 2011, the sample was designed to meet a precision target of plus or minus 10 percent of the total need for each state. Data from 2003 and 2007 were used to estimate the variance in order to calculate the required sample sizes. EPA will update its estimates of the variance using the data from the 2011 Assessment.
      The sample size needed in 2015 can change because of changes in the inventory or changes in the estimated variance of total need by state. In principal, the required sample size can increase or decrease due to these changes. The sample for some states may increase while others may decrease. The allocation among a state's strata may also change, even if the total sample required does not change.
      EPA will revise the sampling plan based on this comment. In cases where the sample size needed increases, EPA will drop 25 percent of the 2011 sample, returning the dropped systems to the pool of systems that can be sampled. EPA will then randomly select the number of additional systems required to meet the precision targets. For example, if the 2011 sample size was 12 and the 2015 sample size must increase to 15 to meet the precision target, EPA will first randomly select and drop 3 systems from the sample and will then randomly select 6 systems from the inventory of remaining systems. The 3 systems that were dropped may get sampled again.
      In cases where the required sample size decreases, EPA will randomly select systems to remove from the sample. It will then randomly select 25 percent of the remaining sample to drop and replace. EPA will then randomly select from the frame -- including systems that were dropped in the first two steps -- systems to replace the 25 percent dropped as part as the refresh.
Other minor comments that may be worth some consideration:
   * One minor point regarding the assessment of small systems. On page 6, it states that "Systems that serve populations fewer than 3,301 will not be surveyed. Their needs will be based on the average system need as calculated in 2011..." The Office of Ground Water and Drinking Water certainly has a better understanding of this than I, and I ultimately defer to their expertise, but my understanding is that in 2011 the average small system needs were inferred from responses to a 2007 survey. Are there any concerns that these data are 8 years old and small system needs may have changed?
         EPA response: In previous assessments, EPA has successfully used the approach of extrapolating earlier survey results based on adjustments for construction cost inflation and shifts in the number and sizes of small water systems.  For the 2015 assessment, EPA believes this approach will provide an accurate accounting of these systems' needs, but upon completion of the 2015 effort, the Agency will evaluate the results in the context of designing the 2019 DWINS.
   * On page 22, equation 2.6, a slight adjustment is made to account for an assumed 90% response rate. However, the 2011 medium facility response rate was listed as 97%. It seems EPA is being conservative by assuming lower response rate than it has achieved in the past. It seems reasonable to be conservative in order to better ensure the desired level of statistical precision. Perhaps this is a feature worth emphasizing?
         EPA response: While we will work to continue to have a higher response rates, EPA will continue to be conservative in setting targeted sample sizes to ensure our precision targets are reached and a credible survey obtained.

Appendix D  -  Comments and Response to Comments Received on the First Federal Register Notice

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