Drinking Water: EPA Has Improved Its Unregulated Contaminant Monitoring Program, but Additional Action Is Needed
Published: 2014-01-09T00:00:00

Fast Facts:

Highlights:
section_title: Why GAO Did This Study
paragraphs: EPA's UCMR program collects data on unregulated contaminants in the nation's drinking water. EPA uses these data and other information to make regulatory determinations-- decisions on whether to regulate additional drinking water contaminants. It is currently in its third data collection cycle, UCMR3.
GAO was asked to examine the UCMR program. This report examines: (1) the extent to which EPA implemented GAO's prior recommendations to improve the program and opportunities, if any, to strengthen it further; (2) the factors EPA considered when it selected the UCMR3 contaminants and the limitations, if any, it faced in selecting them; and (3) the extent to which UCMR data support regulatory determinations.
GAO reviewed EPA documents, surveyed 48 subject matter experts, assessed the UCMR program against statutory requirements and other standards, and interviewed EPA officials.
section_title: What GAO Found
paragraphs: The Environmental Protection Agency (EPA) has implemented all of the recommendations GAO made in its May 2011 report to improve the Unregulated Contaminant Monitoring Rule (UCMR) program. In that report, GAO recommended that EPA (1) monitor for the full 30 contaminants allowed by statute, (2) monitor for most or all contaminants using a more robust monitoring approach, and (3) select sufficiently sensitive minimum reporting levels (MRL) for monitoring contaminants. EPA now requires public water systems to monitor for 30 contaminants in the UCMR3 program, using its most robust monitoring approach for a majority of these contaminants, and setting MRLs as low as can be reliably measured, according to EPA. The Safe Drinking Water Act (SDWA) requires EPA to vary the monitoring frequency based on the type of contaminant likely to be found, but EPA used a standard monitoring frequency for all contaminants. This may result in inaccurate estimates of the occurrence of sporadically occurring microbes (e.g., viruses) or pesticides, according to experts GAO surveyed and studies it reviewed. In such cases, the monitoring data may not provide reliable estimates of contaminant occurrence.
EPA used 10 factors to select the 30 contaminants for UCMR3, but its selection process faced some limitations. Officials told GAO that the contaminants did not have to meet all 10 of the selection factors to be chosen, but 3 were very important (1) the availability of an analytical method to detect contaminants, (2) the reliability of health effects information on the contaminants, and (3) the need for data to support regulatory determinations for priority contaminants. However, EPA is limited by a statutory cap of 30 contaminants every 5 years, which restricts its ability to collect data on additional contaminants that could have been monitored for little additional cost. SDWA's legislative history reflected concerns with the ability of public water systems to absorb such costs, but many of the analytical methods EPA is using for UCMR3 are able to test a single sample of drinking water for more than one contaminant at a time. However, because of the limit of 30, EPA cannot always take advantage of this efficiency and is unable to gain economies of scale using monitoring that is already under way.
EPA uses UCMR data to support regulatory determinations but faces a time lag when doing so. EPA has used UCMR data to support 10 out of 12 regulatory determinations it has made since 2008 and is currently using UCMR data to inform the determinations expected in 2015. However, a time lag between the statutory deadline for making regulatory determinations and when UCMR data are available delays determinations on given contaminants until the following cycle. The 2-year time frame SDWA originally established from the time EPA publishes the UCMR list to when it makes regulatory determinations has not provided enough time for the agency to incorporate the UCMR data into the determinations. The UCMR3 monitoring, data collection, and analysis overlap with the time when EPA will be making its regulatory determinations for contaminants from its most recent Contaminant Candidate List. Consequently, UCMR data are not available to support regulatory determinations for contaminants during the cycle in which they are monitored; rather, UCMR data typically are not used until the next cycle. EPA officials told GAO that most of the UCMR3 data, which are being collected from 2013 to 2015, will be used to support the regulatory determinations it expects to issue in 2020 instead of 2015.
section_title: What GAO Recommends
paragraphs: Congress should consider amending the Safe Drinking Water Act to allow EPA to monitor for more than 30 contaminants under certain circumstances, and to adjust statutory time frames so UCMR data can inform regulatory determinations in the same cycle. GAO, among other things, recommends that EPA vary the monitoring frequency based on contaminant type. In commenting on a draft of this report, EPA generally agreed with GAO’s findings, conclusions, and recommendations.

section_title: Letter
paragraphs: Most Americans receive their drinking water from the more than 160,000  public water systems in the United States, all of which are subject to key  requirements of the Safe Drinking Water Act (SDWA). Under SDWA, the  Environmental Protection Agency (EPA) is authorized to regulate  contaminants in public water systems. Currently, EPA regulates more  than 89 drinking water contaminants. In 1996, in the midst of concerns  about the number and pace of regulations required under the act and the  need to better focus limited resources on contaminants of greatest public  health concern, Congress enacted significant amendments to SDWA. The  1996 amendments to SDWA also directed EPA, among other things, to  identify unregulated contaminants that present the greatest public health  concern, establish a program to monitor drinking water for unregulated  contaminants, and decide whether or not to regulate at least 5 such  contaminants every 5 years. EPA decisions about whether or not to  regulate these contaminants are called regulatory determinations. Since  1996, EPA has made 21 regulatory determinations and has decided to  regulate one of the contaminants, perchlorate. EPA has identified 116  unregulated contaminants, including perchlorate and others such as  formaldehyde and Salmonella enterica, that it believes may occur in  public water systems and may also require regulation. Those unregulated  contaminants are listed on EPA’s current Contaminant Candidate List  (CCL).
In addition, EPA has established the Unregulated Contaminant Monitoring  Rule (UCMR) program, to monitor drinking water for unregulated  contaminants, under the 1996 amendments to SDWA. As part of the  UCMR, the SDWA amendments require EPA to issue a list every 5 years  identifying up to 30 contaminants to be monitored by public water  systems. The UCMR program is currently in its third 5-year cycle, known  as UCMR3. EPA estimates that UCMR3 will cost $87 million from 2012 to  2016, of which $21 million will be paid by EPA. EPA will pay for small  water systems’ costs for the UCMR; the remaining $66 million will be paid  by large water systems. The UCMR, CCL, and regulatory determinations  are related to each other. First, the CCL identifies unregulated  contaminants that may require regulation in the future. Through the  UCMR program, public water systems monitor for some of the CCL  contaminants to determine how often and at what level the contaminants  occur in drinking water. EPA then makes regulatory determinations about  contaminants on the CCL using UCMR data, information about the  contaminants’ health effects, and other information for support.
In May 2011, we reported that EPA’s monitoring program under the  UCMR did not use EPA’s full statutory authority under SDWA, use  sufficiently sensitive testing methods, or employ sufficiently robust  monitoring approaches. First, EPA did not use its full allotment of 30  contaminants as authorized by SDWA in either of the first two UCMR  cycles (UCMR1 and UCMR2), which limited the agency’s progress in  obtaining data on drinking water contaminants. Second, in some cases,  EPA required public water systems to use testing methods (i.e., analytical  methods) that were not sufficiently sensitive to identify the presence of  contaminants at EPA’s health reference level—the health benchmark  EPA uses in assessing whether to regulate specific contaminants. Third,  EPA used a limited sample size of 300 public water systems for UCMR1  for one of the program’s monitoring approaches, which resulted in  occurrence data that, according to EPA documents, were not sufficient to  make national estimates of contaminant occurrence. In the 2011 report,  we also recommended that EPA use its full statutory authority to monitor  for 30 unregulated contaminants, select minimum reporting levels that are  sufficiently sensitive to detect the presence of contaminants in public  water systems at levels of public health concern, and monitor for most or  all contaminants using the program’s most robust monitoring approach.
In this context, you asked us to examine the UCMR program. Specifically,  our objectives for this report were to: (1) evaluate the extent to which EPA  has implemented the recommendations we made in 2011 to improve the  UCMR program and identify any opportunities to strengthen it further; (2)  identify the factors that EPA considered when it selected the  contaminants for monitoring under UCMR3 and the limitations, if any, that  EPA faced in selecting the contaminants; and (3) examine the extent to  which UCMR data support regulatory determinations.
To identify the steps EPA has taken in response to the recommendations  we made in 2011, we reviewed EPA documents, including EPA’s  proposed and final rules for the UCMR program, assessed the UCMR  sample design against statutory requirements and statistical standards,  and interviewed EPA officials. To identify the factors EPA considers when  selecting contaminants, we reviewed EPA documents, including EPA’s  proposed and final rules for the UCMR program and SDWA requirements,  and interviewed EPA officials. To determine how EPA uses the UCMR  data to support its regulatory determinations, we reviewed EPA and  Federal Register documents and interviewed EPA officials. In addition, to  obtain further information about the UCMR program and identify  opportunities to strengthen it further, we conducted a two-round Delphi  survey of experts selected for their knowledge of one or more of the  following areas: drinking water, contaminant monitoring, analytical  methods, toxicology, risk assessment, and environmental regulation. In  the first round of the survey, we selected 14 experts who demonstrated  familiarity with EPA’s CCL, UCMR, and regulatory determination  processes. We asked them 10 open-ended questions about how various  aspects of the UCMR program helped or hindered EPA in (1) selecting  priority contaminants, (2) monitoring for selected contaminants, and (3)  using the data to support regulatory determinations. We analyzed the  responses provided by the experts and developed closed-ended  questions for the second round of the survey. To identify experts for the  second round of the survey, we developed a preliminary list of experts,  which included the 14 experts who completed the first round of the survey  and others identified through interviews with stakeholders and our review  of public comments provided on EPA’s proposed rules. We contracted  with the National Academy of Sciences to identify additional experts. We  selected 48 experts for the second round of the survey based on their  knowledge of one or more of the following topic areas: drinking water,  contaminant monitoring, analytical methods, toxicology, risk assessment,  and environmental regulation. For the first round of the survey, we  received responses from 14 of the 14 experts we surveyed and, for the  second round, we received responses from 40 of 48 experts we surveyed  (83 percent response rate). The information that we obtained from the  expert surveys is not generalizable to all experts that have an interest in  or knowledge of drinking water contaminant monitoring but does provide  several experts’ views on the UCMR program. For more information on  our objectives, scope, and methodology see appendix I. See appendix IV  for a copy of the survey questions and responses for the second round of  the survey and appendix V for a list of the experts who completed the  surveys.
We conducted this performance audit from June 2012 to January 2014 in  accordance with generally accepted government auditing standards.  Those standards require that we plan and perform the audit to obtain  sufficient, appropriate evidence to provide a reasonable basis for our  findings and conclusions based on our audit objectives. We believe that  the evidence obtained provides a reasonable basis for our findings and  conclusions based on our audit objectives.
subsections: section_title: Background
paragraphs: This section presents information on (1) regulated and unregulated  contaminants in drinking water, (2) the UCMR program and SDWA  requirements, and (3) laboratories and methods used to analyze drinking  water.
subsections: section_title: Regulated and Unregulated Contaminants in Drinking Water
paragraphs: Drinking water contaminants include chemical and microbial substances,  some of which can harm human health. For example, prolonged exposure  to arsenic in drinking water can cause skin damage or circulatory  problems and, over time, may increase cancer risks. Contaminants may  be naturally occurring or introduced through other means. EPA has  identified three ways that drinking water generally becomes  contaminated. First, contaminants can find their way into drinking water  sources from industrial waste releases, agricultural runoff, and other  pollution sources. Second, contamination can occur during the treatment  of water by forming what are known as “disinfection by-products.” Third,  contaminants can “leach” or dissolve out of the materials used for  treatment, storage, and distribution of water.
EPA regulates drinking water contaminants under SDWA by issuing  legally enforceable standards, known as National Primary Drinking Water  Regulations or “primary standards” that generally limit the levels of these  contaminants in public water systems. EPA has issued primary standards  addressing more than 89 contaminants. States generally enforce these  standards through compliance monitoring. Under compliance monitoring,  public water systems collect a sample of drinking water, analyze the  sample for specific contaminants, and report the results to states. To  analyze the samples, water systems and states use analytical methods  developed by government agencies, universities, and other organizations.  EPA evaluates analytical methods for drinking water and approves those  it determines meet agency requirements for monitoring contaminants.  Laboratories analyzing drinking water compliance samples must be  certified by the state or EPA. EPA establishes schedules for how often  water systems must monitor for regulated contaminants. The monitoring  frequency generally depends on the contaminant, previous monitoring  results, the type of source water, and the size of the population served by  the water system.
Unregulated drinking water contaminants include chemical and microbial  substances and are not currently subject to primary standards under  SDWA. Exposure to unregulated drinking water contaminants may pose  a human health risk, particularly to vulnerable subpopulations such as  pregnant women, infants, the elderly, and those with compromised  immune systems. Unregulated contaminants include industrial  chemicals, military chemicals, pesticides, bacteria, and other microbes  and chemicals. They also include contaminants of emerging concern—  contaminants characterized by a perceived, potential or real threat to  human health or the environment or by a lack of published health  standards. Examples include pharmaceuticals, such as prescription and  over-the-counter drugs, and ingredients in personal care products, such  as cosmetics and soaps. A contaminant may also be considered to be  emerging because a new source of public exposure has been discovered  or a new detection method or treatment technology has been developed.
section_title: UCMR Program and SDWA Requirements
paragraphs: Under the UCMR program, EPA collects data about the occurrence of  unregulated contaminants in drinking water. The UCMR program collects  data on the extent of the occurrence of unregulated contaminants in all  public water systems serving more than 10,000 people and in a nationally  representative sample of smaller systems. These data inform EPA’s  decisions about whether to issue primary standards for unregulated  contaminants. Under the UCMR, EPA is to identify up to 30 unregulated  contaminants that may be present in drinking water and establishes a  monitoring program to obtain data on the extent of their occurrence.  These data help EPA determine whether drinking water contamination is  occurring and estimate its level and frequency. EPA established a three- tiered approach for monitoring UCMR contaminants that includes (1)  assessment monitoring, (2) screening survey, and (3) pre-screen testing.  EPA’s approach is based primarily on the availability of analytical  methods to monitor the contaminants. Assessment monitoring is used to  monitor contaminants that can be detected by well-established analytical  methods that are widely used in drinking water laboratories. The  screening survey is used to monitor contaminants that can be detected by  more recently developed analytical methods that are used in fewer  drinking water laboratories. Pre-screen testing is used to monitor  contaminants that can be detected by very new or specialized analytical  methods that are used in a small set of drinking water laboratories.
Approximately 6,000 public water systems are currently participating in  the UCMR program. Participating public water systems are monitoring for  contaminants under one or more of the three tiers. EPA varies the  number of public water systems required to monitor under each tier.  UCMR monitoring is conducted by all large community and nontransient,  noncommunity public water systems serving more than 10,000 people.  Monitoring is also conducted by a nationally representative sample of  other public water systems that EPA selects (see table 1). In addition, a  sample of community and nontransient, noncommunity water systems,  and transient water systems are required to allow EPA to conduct pre- screen testing under UCMR3.
The UCMR program is part of a larger framework established by SDWA  that also includes the CCL and requires EPA to make regulatory  determinations for at least five of the contaminants on that list every 5  years. The CCL is a list of unregulated contaminants that are known or  anticipated to occur in public water systems and that may require  regulation. SDWA directs EPA to select contaminants that pose the  greatest public health concern for consideration for the CCL and  regulatory determinations. A regulatory determination is a formal  decision on whether EPA should initiate a rulemaking process to develop  a primary standard for a specific drinking water contaminant. The UCMR,  CCL, and regulatory determinations framework is implemented by three  different branches within EPA’s Office of Ground Water and Drinking  Water’s Standards and Risk Management Division: the Technical Support  Center administers the UCMR program; the Targeting and Analysis  Branch develops the CCL; and the Standards and Risk Reduction Branch  leads the development of the regulatory determinations.
SDWA requires EPA to make regulatory determinations for at least five of  the contaminants on the CCL every 5 years. Regulatory determinations  can be positive (i.e., a primary standard is needed) or negative (i.e., no  primary standard is needed). Under SDWA, EPA is to make a positive  regulatory determination and subsequently issue a primary standard  when (1) the contaminant may have an adverse effect on the health of  persons; (2) the contaminant is known to occur or there is a substantial  likelihood that the contaminant will occur in public water systems with a  frequency and at levels of public health concern; and (3) in the sole  judgment of the Administrator, regulation of such contaminant presents a  meaningful opportunity for health risk reduction for persons served by  public water systems. EPA can make a negative regulatory determination  when the SDWA conditions are not met. SDWA set recurring 5-year  deadlines for the CCL, UCMR, and regulatory determinations. The initial  deadlines were staggered such that EPA was required to publish the CCL  in the Federal Register first (February 1998), the UCMR list 18 months  later (August 1999), and the regulatory determinations 2 years after that  (August 2001). The cycle restarts with the next CCL, UCMR, and  regulatory determinations due 5 years after the first set of deadlines.  However, EPA has not always met the SDWA deadlines. Moreover, EPA  has not issued the CCL, UCMR, and regulatory determinations separated  by the 18-month and 2-year time frames that were originally established  by statute. The cycle is currently in its third iteration. EPA refers to the  programs in the current cycle as CCL3, UCMR3, and the CCL3 regulatory  determinations (see table 2).
The UCMR program’s primary purpose is to inform regulatory  determinations, but EPA can also use the UCMR data to develop health  advisories for some of the contaminants it decides not to regulate. Health  advisories provide information on contaminants that can harm human  health and are known or anticipated to occur in drinking water. They  provide technical guidance on health effects to assist EPA regional  offices, states, and other public health officials. EPA has issued new or  updated health advisories for nine contaminants it decided not to  regulate. The advisories identify concentrations of contaminants at  which adverse health effects are not anticipated to occur over specific  exposure durations (1 day, 10 days, several years, and a lifetime).  Drinking water health advisories are not legally enforceable standards  and, according to EPA, are subject to change as new information  becomes available.
section_title: Laboratories and Methods Used to Analyze Drinking Water
paragraphs: Private analytical laboratories and some water utilities’ laboratories  conduct the analytical testing for the UCMR contaminants. All laboratories  conducting analyses for UCMR3 must be approved by EPA. In general,  laboratories must first successfully complete the registration and  application process, which includes testing for contaminants using EPA- specified analytical methods, before receiving EPA’s approval.  Approved laboratories must adhere to the quality assurance and quality  control procedures and criteria outlined in the methods and rule language  to maintain their approval status and may be subject to on-site laboratory  or paper audits. Laboratories also post occurrence data and required  quality control data electronically in EPA’s data system, the Safe Drinking  Water Accession and Review System, within 120 days of the sample  collection date.
EPA specifies the analytical methods that laboratories participating in the  UCMR program use to detect contaminants. Some methods can detect a  single contaminant while others can detect a group of similar  contaminants. Because the UCMR collects nationwide data, agency  officials told us EPA’s goal is to use analytical methods that yield  consistently high-quality monitoring data from public water systems  across the country. EPA officials told us that the agency develops or uses  analytical methods for the UCMR program that enable it to meet this goal.  In particular, agency officials told us these methods must (1) have  sufficient “holding times”; (2) be able to be used successfully by a  variety of labs with varying levels of expertise; and (3) be used effectively  in different types of drinking water. EPA officials said it typically takes 1 or  2 years to develop a standard analytical method that meets these  requirements and up to 3 years or longer to develop more complex  methods. See appendix III for more information on analytical methods.
section_title: EPA Has Improved the UCMR Program by Implementing Our Recommendations, but Its Monitoring Frequency May Yield Some Inaccurate Estimates
paragraphs: EPA has implemented the three recommendations we made in our May  2011 report to improve the UCMR program. The technical changes EPA  has made to UCMR3 are significant improvements over prior UCMR  cycles and have increased the program’s productivity and statistical  strength, among other things. However, the program’s monitoring  frequency may result in inaccurate estimates of the occurrence of some  contaminants.
subsections: section_title: EPA Has Implemented All of GAO’s 2011 Recommendations to Improve the UCMR Program
paragraphs: In UCMR3, EPA implemented our recommendations to (1) monitor for 30  contaminants; (2) monitor for most or all contaminants using the  program’s more robust monitoring approach; and (3) select minimum  reporting levels (MRL) that are sufficiently sensitive to detect the  presence of contaminants in public water systems at levels of public  health concern as follows:  Monitor for 30 contaminants. In our May 2011 report, we reported that  EPA did not use its full statutory authority to monitor for 30 contaminants  in implementing the first two cycles of the UCMR program. Specifically,  EPA required that 26 and 25 contaminants be monitored under UCMR1  and UCMR2, respectively. As a result, EPA did not obtain occurrence  data for 9 additional contaminants, which in turn, limited the agency’s  productivity in obtaining critical information to support its regulatory  determinations. In its response to our recommendation that it use its full  statutory authority, EPA stated it supports a goal of including as many  priority contaminants as possible in each 5-year monitoring cycle.  Accordingly, in May 2012, EPA published its final rule for UCMR3  requiring public water systems to monitor for 30 contaminants (see app. II  for a list of the 30 contaminants).
Use more robust monitoring approach. In 2011, we reported that EPA  officials described the assessment monitoring approach as “the gold  standard” for obtaining sufficient data on national occurrence of drinking  water contaminants to support regulatory determinations, but that it had  used the more limited screening survey approach for a majority of the  contaminants monitored under UCMR1 and UCMR2, as shown in table 3.  The screening survey monitoring approach produces estimates of  national occurrence with greater uncertainty than those provided by  assessment monitoring because it requires a smaller sample of public  water systems to monitor. For example, under UCMR1, the screening  survey required a sample of 300 public water systems to monitor. In  contrast, approximately 3,800 systems were required to conduct  assessment monitoring. In EPA’s response to our recommendation that it  conduct monitoring for most or all contaminants using the assessment  monitoring approach, EPA stated that it supports a goal of using  assessment monitoring for as many contaminants as is practical to obtain  more robust occurrence data for and also to achieve higher confidence in  the national estimates. EPA is requiring assessment monitoring for a  majority of the contaminants under UCMR3. In addition, for UCMR2 and  UCMR3, EPA expanded the sample size of the screening survey to  increase the statistical strength of the monitoring results. We analyzed  EPA’s methodology for selecting the sample of systems for the screening  survey under UCMR2 and UCMR3 against standard statistical criteria,  and we determined that the larger sample size should allow EPA to make  national estimates of contaminant occurrence with smaller margins of  error and higher levels of confidence compared with the first UCMR. In  addition, 26 of the 40 experts who participated in our survey thought the  screening survey monitoring approach for UCMR3 is likely to provide EPA  with sufficient data to determine whether contaminants occur with a  frequency and at levels of public health concern. Further, EPA officials  told us that the UCMR2 screening survey occurrence data are sufficient  for supporting regulatory determinations, whereas, in its 2008 regulatory  determinations notice, EPA stated that the occurrence data were  insufficient to support regulatory determinations for 12 of the 14  contaminants monitored under the UCMR1 screening survey.
Select sufficiently sensitive MRLs. In 2011, we reported that the utility of  the UCMR occurrence data was reduced because EPA had not used  sufficiently sensitive MRLs to detect the presence of contaminants at  levels of public health concern. Specifically, for 9 of the 20 contaminants  for which EPA made regulatory determinations in 2003 and 2008, the  MRL exceeded EPA’s health reference level—the health benchmark EPA  uses to assess whether the detection of a specific contaminant may  indicate a potential human health risk. As a result, occurrence of these 9  contaminants at a level higher than the health reference level, but lower  than the MRL, may not have been detected. In its response to our  recommendation that EPA use MRLs that are sufficiently sensitive, EPA  stated it supports a goal of establishing minimum reporting levels that are  sufficiently sensitive to reliably detect the known and likely occurrence of  contaminants in public water systems at levels of public health concern  and provide useful and credible information on the occurrence of the  contaminants in public drinking water systems. EPA has since revised  its approach for selecting MRLs for monitoring selected contaminants in  an effort to increase the likelihood that the monitoring will be sufficiently  sensitive to detect the presence of contaminants at levels of public health  concern. Specifically, EPA officials told us that, for UCMR3, the agency  set the MRLs based on how low the method could reliably measure  specific contaminants. These levels are based on method sensitivity  (i.e., not adjusted upward based on available health effects information).  In some cases, the MRLs for UCMR3 are set well below EPA’s current  health reference levels, according to EPA’s final rule for UCMR3.  However, health effects research on some UCMR3 contaminants is still in  progress, and the health reference levels are subject to change. EPA  believes that its new approach will be more effective than its past  approach because, by monitoring for contaminants at the lowest  concentrations feasible, UCMR3 is more likely to detect contamination at  levels of public health concern, even if new health effects data result in  lower health reference levels in the future, as anticipated by its final rule  for UCMR3.
section_title: UCMR Monitoring Frequency May Yield Inaccurate Estimates of Some Contaminant Occurrence
paragraphs: EPA has taken steps to improve the UCMR program, but the program’s  standard monitoring frequency may result in inaccurate estimates of the  occurrence of certain contaminants. In particular, several experts we  surveyed and studies on contaminant occurrence indicated that the  UCMR3 standard monitoring frequency may result in inaccurate  estimates of the occurrence of sporadically occurring microbes (e.g.,  viruses) and seasonally applied pesticides. SDWA calls for EPA to vary  the monitoring frequency and schedule for public water systems based on  three criteria (1) the number of persons served by the system, (2) the  source of the system’s water supply, and (3) the contaminants likely to be  found. Under UCMR3, EPA varies the monitoring frequency for systems  based on a system’s size and water supply (e.g., surface water or  groundwater), but it does not vary it based on the type of contaminant  likely to be found. Specifically, under UCMR3, surface water systems and  groundwater systems under the direct influence of surface water are  required to conduct quarterly monitoring of selected chemical  contaminants, while groundwater systems are required to monitor  selected chemical contaminants twice a year. In addition, nondisinfecting  groundwater systems that serve 1,000 or fewer people and are located in  sensitive hydrogeological areas are required to allow EPA monitoring for  two microbial contaminants (viruses) twice a year (see table 4). The virus  monitoring in UCMR3 was designed in consideration of where these  viruses may be more likely to be found—small groundwater systems that  do not disinfect. Nonetheless, EPA used the standard monitoring  frequency for viruses; it did not vary the frequency or schedule based on  the contaminants likely to be found. Similarly, contaminant monitoring  under UCMR2 occurred quarterly for surface water systems and twice a  year for groundwater systems for all contaminants. EPA did not vary the  monitoring frequency or schedule during the seasons when pesticides  were applied and the likelihood of occurrence was highest.
When EPA first established the UCMR program, it explained that the  standard monitoring frequency for public water systems using surface  water and groundwater under the direct influence of surface water will  capture variability in contaminant occurrence because one of each public  water system’s quarterly sampling events must occur during what EPA  considers to be the most vulnerable period for drinking water  contamination, i.e., the period of peak contamination. According to  EPA’s explanation in the Federal Register accompanying the final rule for  UCMR1, studies show that the greatest risk of contaminant occurrence  for much of the country is the late-spring/early-summer runoff period from  May to July, particularly for contaminants such as pesticides and nitrate.  EPA designed the UCMR3 program to include sampling during this  period, as designated by EPA or the state. Quarterly monitoring for  systems using surface water or groundwater under the direct influence of  surface water occurs during one of three possible time frames (1)  January, April, July, and October; (2) February, May, August, and  November; or (3) March, June, September, and December. EPA assigns  one of these three time frames to each participating public water system  using surface water or groundwater under the direct influence of surface  water. EPA did not specify a vulnerable period for public water systems  using groundwater in UCMR2 and UCMR3, but it stated that samples will  be taken during all months and seasons of the year when all groundwater  systems are considered together, according to agency documents.
However, several experts we surveyed and studies on contaminant  occurrence indicated that the UCMR standard monitoring frequency may  not accurately characterize the presence of certain contaminants in public  water systems. In particular, the monitoring frequency may result in  inaccurate estimates of the occurrence of sporadically occurring microbes  (e.g., viruses) and pesticides whose peak concentrations typically occur  during and after the application season, primarily from April through July.  For example, EPA’s monitoring frequency may underestimate occurrence  for compounds such as seasonally applied pesticides, according to one  expert we surveyed.
As noted above, the UCMR3 standard monitoring frequency may result in  inaccurate estimates of the occurrence of some microbes and pesticides.
Microbes. Under UCMR3, EPA selected a representative sample of  800 nondisinfecting groundwater systems located in sensitive  hydrogeological areas to monitor for two viruses—enterovirus and  norovirus—using the pre-screen testing monitoring approach. In the  notice for its proposed rule for UCMR3, EPA states that the agency  limited its selection to those systems serving 1,000 or fewer persons  because these smaller systems are the least likely to disinfect the  water and, therefore, the most vulnerable to contamination with  viruses. Monitoring and analyses are organized and paid for by EPA  through direct contracts with laboratories. Under UCMR3, each of the  selected systems will be monitored for the viruses twice during a 12- month period from January 2013 to December 2015. The systems’  sampling events will be 5 to 7 months apart. However, more than half  of the experts who completed our survey (23 of 40) said the twice- yearly monitoring requirement for viruses is not likely to provide EPA  sufficient data to determine whether the contaminants occur with a  frequency and at levels of public health concern. In addition, 15  experts who completed our survey stated that more frequent  monitoring may be warranted to capture the occurrence of viruses in  public water systems, which many characterized as variable.  Similarly, a technical presentation that EPA used to support its  rationale for including the viruses in UCMR3 shows that virus  occurrence in groundwater systems is highly variable and that  groundwater recharge events, like heavy precipitation, increase virus  contamination levels. The technical presentation concludes that  more frequent sampling is necessary to characterize virus occurrence  in public water systems. Moreover, in the past, EPA varied the  monitoring frequency for a microbe that public comments on EPA’s  proposed rule for UCMR1 characterized as sporadically occurring.  Specifically, under UCMR1, surface water systems and groundwater  systems monitoring for the microbial contaminant, Aeromonas, were  required to take samples quarterly, with additional samples taken, so  that samples generally were collected each month during the warmest  months of the year (July, August, and September) because EPA  officials told us that this is when they expected to find contaminant  occurrence. Systems monitored during one of three possible time  frames (1) January, April, July, August, September, and October; (2)  February, May, July, August, September, and November; or (3)  March, June, July, August, September, and December. In contrast,  UCMR3 does not require any additional monitoring for viruses. As a  result, the data obtained under UCMR3 may not provide reliable  estimates of the occurrence of viruses in drinking water.
Pesticides. Under UCMR2, all public water systems serving 100,000  or more people and a representative sample of 800 systems serving  fewer than 100,000 people were required to monitor for nine  pesticides using the screening survey monitoring approach. These  pesticides included three widely used herbicides applied for weed  control on crops such as corn, cotton, and soybeans, and six  degradates. Contaminant monitoring occurred quarterly for surface  water systems and biannually for groundwater systems. No additional  monitoring was conducted during the seasons when pesticides were  applied and the likelihood of occurrence was highest. Two of the 14  experts who participated in the first round of our survey said that the  UCMR standard monitoring frequency may result in inaccurate  estimates of the occurrence of such pesticides in public water  systems. For example, one expert said that, following application,  pesticides can occur at relatively high concentrations but for short  periods of time, and that, because the UCMR’s timing and frequency  of monitoring are not based on this consideration, the program could  completely miss that occurrence. Data from a United States  Geological Survey (USGS) report also show that concentrations of  herbicides are usually highest during and after the application season,  primarily from April through July. For example, at four stream sites  studied, USGS found that the presence of atrazine, the dominant  herbicide used in the Corn Belt during the study period, typically  peaked after applications in the spring and gradually declined through  the summer and winter. According to the USGS report, such seasonal  patterns of pesticide concentrations are generally consistent each  year, as long as the pesticides are still in use. Pesticide occurrence in  groundwater also generally coincides with pesticide use patterns.  Sampling was conducted throughout the year, including intensive  sampling during the times of highest pesticide use and runoff. This  sampling approach enabled USGS to conclude that concentrations of  pesticides in streams and groundwater were typically below water- quality benchmarks for human health. Thus, seasonal monitoring of  pesticides is important to assess whether pesticides occur at  concentrations that may affect human health. Also, high-frequency  sampling during seasons when intense pesticide use coincides with  periods of high runoff may be needed to ensure that the highest  pesticide concentrations are detected. In contrast, EPA’s standard  monitoring frequency requires most public water systems to monitor  for contaminants only once per season or once over two seasons. As  a result, some of the data collected under UCMR2 may not yield  accurate estimates of pesticide occurrence in public water systems.
section_title: EPA Considered 10 Factors to Select Contaminants for Monitoring, but Its Selection Process Faced Limitations
paragraphs: EPA used 10 selection factors, as well as a working group, and internal  and external reviews, among other steps, to select contaminants for  UCMR3. However, the process was lengthy due primarily to the reviews  and the time required to develop analytical methods. The selection  process was also limited by a statutory cap of 30 contaminants, which  restricted EPA’s ability to collect data on additional contaminants that  could have been monitored for very little additional cost. The selection  process also excluded contaminants previously monitored in earlier  UCMR cycles, which has some limitations.
subsections: section_title: UCMR3 Contaminant Selection Considered Multiple Factors, but the Process Was Lengthy
paragraphs: To select contaminants for UCMR3, EPA considered 10 factors and used  a prioritization process to identify potential contaminants, but took over 30  months, or 2 ½ years, to develop and publish the final list in the Federal  Register after the CCL was published. Had EPA consistently met the  initial and recurring statutory deadlines for CCL and UCMR, they would  have been separated by 18 months.
subsections: section_title: Contaminant Selection Factors
paragraphs: EPA used 10 factors to select contaminants for UCMR3 (see fig. 1).  Officials told us that a contaminant does not have to meet all of the  selection factors to be chosen; however, three are very important to  consider as follows:
Analytical method availability. Because analytical methods are the  means by which laboratories test for contaminants, EPA officials told  us they could not include a contaminant on the UCMR list without also  having an analytical method available that is sensitive and precise  enough to provide the data quality and accuracy that EPA needs for  the UCMR program. See appendix III for more information on  analytical methods.
Health effects information. Because of the importance of monitoring  for UCMR contaminants that may pose a public health risk and,  therefore, may need to be regulated, EPA officials told us they placed  a high priority on contaminants for which they have reliable health  effects data.
Need for data to support regulatory determinations on priority  contaminants. Because the goal of the UCMR program is to provide  occurrence data on unregulated contaminants for informing regulatory  determinations, the Standards and Risk Reduction Branch’s priorities  for data to support a regulatory determination are heavily considered.
According to EPA documents and officials, EPA used a prioritization  process to select potential UCMR3 contaminants. First, EPA considered  the contaminants listed on CCL3 and identified contaminants of emerging  concern to establish an initial list of about 150 contaminants.  Contaminants for which analytical methods were not available were then  eliminated from consideration for UCMR3, however EPA officials told us  that those contaminants may be monitored under a future UCMR if an  analytical method can be developed. Contaminants that were monitored  under UCMR1 or UCMR2 were also eliminated from further consideration  early in the UCMR3 selection process, as reported in the Federal  Register and agency records. These two selection factors reduced the  list to fewer than 35 contaminants, according to EPA documentation. In  addition, officials told us they met regularly with representatives from the  Standards and Risk Reduction Branch to ensure the list of UCMR  contaminants would meet their needs for data to support regulatory  determinations.
EPA finalized the UCMR3 list through deliberations with other EPA staff  and stakeholders and by holding internal and external reviews, among  other steps (see fig. 2). In November 2009, a UCMR3 working group led  by EPA’s Technical Support Center and composed of EPA national and  regional staff, as well as representatives from states, began to select the  final 30 contaminants. The EPA Office of Science and Technology  conducted health effects evaluations for possible UCMR3 contaminants,  according to EPA documents and agency officials. The UCMR3 working  group, whose members included experts from the Office of Science and  Technology, reviewed this health effects information. For each UCMR3  chemical contaminant, EPA developed an information sheet that listed  known health effects information and the sources of that information,  among other things. EPA used these contaminant information sheets for  internal considerations and published them in the EPA docket for  UCMR3. After the working group discussed the list of contaminants, the  Technical Support Center submitted the proposed and final UCMR  contaminant lists and associated rules to EPA management for their  review. The EPA internal reviews involved different offices within EPA,  including the Office of the EPA Administrator. EPA also submitted the  proposed and final UCMR lists and rules to the Office of Management  and Budget (OMB) for its review. On March 3, 2011, EPA published a  proposed list of 30 contaminants and the associated rule in the Federal  Register. EPA published the final UCMR3 contaminant list and associated  rule on May 2, 2012 (see app. II for list of UCMR3 contaminants).
The UCMR3 selection process led EPA to select many contaminants from  the CCL, EPA’s list of the unregulated drinking water contaminants that  may require regulation because they are known or anticipated to occur in  public water systems. Specifically, 22 of the UCMR3 contaminants were  also listed on CCL3. The CCL3 process was developed using substantial  expert input and recommendations from various groups, including the  National Academy of Science’s National Research Council, the National  Drinking Water Advisory Council, and EPA’s Science Advisory Board,  according to EPA documents. In addition, 37 of the 40 experts who  participated in our survey said that CCL3 was a reasonable source for  EPA to use when it began identifying contaminants for UCMR3. UCMR3  also included 7 contaminants of emerging concern that were not on  CCL3, and total chromium. Further, 33 of the 40 experts said it was  worthwhile for EPA to select contaminants for the UCMR that are not on  the CCL. For example, one expert in our survey told us that including  such contaminants is the best way to identify emerging contaminants that  come to light between the publication of the CCL and UCMR list. Overall,  30 of the 40 experts who participated in our survey reported that the  contaminants EPA selected for UCMR3 warrant monitoring.
section_title: Contaminant Selection Process Was Lengthy
paragraphs: EPA’s UCMR3 contaminant selection and rule development process took  more than 2 ½ years to complete. EPA started the formal UCMR3  selection process in November 2009 but did not publish the final UCMR3  list until May 2012. SDWA specifies that EPA publish a new UCMR list  every 5 years. Whereas EPA’s previous list was issued in 2007, it met the  5-year time frame required by SDWA. However, the UCMR program is no  longer staggered 18 months after the CCL, as SDWA intended. Rather,  UCMR3 was issued 31 months after CCL3. Based on the length of its  process, EPA would have had to begin selecting contaminants in  September 2008 to have issued UCMR3 within 18 months of CCL3.  Further, EPA cannot implement the UCMR program until it publishes the  final UCMR list and rule in the Federal Register, which delays the onset of  the data collection period. This delay, in turn, delays the availability of the  UCMR data for making regulatory determinations (see fig. 3).
The UCMR3 contaminant selection and rulemaking process concluded 31  months after the CCL was issued primarily because EPA waited to initiate  its working group until CCL3 was finalized, and the EPA and OMB  reviews were lengthy. First, EPA’s UCMR3 working group did not begin  its work until November 2009, after the final CCL3 had been published in  October 2009. EPA officials told us that discussions about potential  contaminants for UCMR3 and analytical methods that were likely to be  available to detect them began earlier, but they waited until November  2009 to begin the formal selection process, in part, because of staffing  needs. The staff who developed UCMR3 were also coordinating and  providing technical support to the public water systems that were  monitoring for contaminants under UCMR2, which took place between  January 2008 and December 2010. In addition, CCL staff serve on the  UCMR working group, and UCMR staff also serve on the CCL working  group, which EPA officials told us limits their availability. Second, EPA  internal reviews, OMB reviews, and the revisions to the UCMR3 proposed  and final rules prompted by the reviewers’ comments added 16 months in  total to the process. However, these reviews are not always required for  this type of activity, according to agency guidance. Specifically, EPA’s  UCMR is conducted under the agency’s Action Development Process, a  process used for developing rules. The agency incorporated EPA  management and OMB reviews into their process; however, these  reviews are not always required for a program like the UCMR, according  to agency guidance, as stated earlier.
In addition, the EPA analytical method development process is complex,  technically challenging and lengthy, which agency officials also told us  presents a challenge for EPA to meet its deadline. EPA officials said it  typically takes 1 to 2 years to develop a standard method that meets the  requirements needed for the UCMR program and up to 3 years or longer  for more complex methods. In addition, EPA generally has not used a  specific analytical method in more than one UCMR cycle, although some  of those older methods could be used to monitor unregulated  contaminants for which EPA does not yet have UCMR occurrence data.  For example, an analytical method used under UCMR1 could have  detected seven CCL3 contaminants, but this method was not included in  UCMR3. According to industry organizations and EPA officials, EPA did  not formally reach out to stakeholders when developing analytical  methods for UCMR 1, 2, or 3. However, EPA is formally reaching out to  stakeholders to get their input on the development of analytical methods  that may be used for UCMR4. In May 2013, EPA held a public meeting  and webinar to provide stakeholders with an update on analytical  methods that EPA has completed or has under development for potential  use in the UCMR program and requested input from attendees to help  address some of the technical challenges it faces.
section_title: Statutory Cap of 30 Contaminants Limits EPA’s Ability to Obtain Additional Data at Little Extra Cost
paragraphs: The statutory cap limiting the UCMR program to 30 unregulated  contaminants every 5 years (i.e., each UCMR cycle) impedes EPA’s  ability to obtain occurrence data on additional contaminants that could be  monitored for little additional effort or cost. Many of the analytical methods  that EPA is using for UCMR3 are able to test a single sample of drinking  water for more than one contaminant at a time. Therefore, data on  additional contaminants could be obtained without additional sampling by  the public water systems. EPA is allowing laboratories to use eight EPA- developed analytical methods to test for UCMR3 contaminants and four  methods developed by others. These methods can detect a total of 67  unregulated contaminants, including 4 listed on CCL3 and 8 contaminants  of emerging concern, according to our analysis of EPA data. There is  broad recognition throughout the federal government that agencies need  to operate programs efficiently and maximize efficiencies when possible.  In addition, EPA officials who use the UCMR data to make regulatory  determinations, while sensitive to the practical limitations of monitoring for  additional contaminants, said that it would be helpful to have additional  UCMR data if a method already in use for UCMR could detect the  occurrence of additional contaminants. However, because of the SDWA  limit of 30 contaminants, EPA cannot always take advantage of this  efficiency and is unable to gain economies of scale by monitoring for  additional contaminants using monitoring that is already under way.
Specifically, our analysis indicates that four CCL3 chemicals—1,1,1,2- Tetrachloroethane; n-propylbenzene; sec-butylbenzene; and methyl  tertiary-butyl ether (MTBE)—could have been detected using one of the  UCMR3 analytical methods. As noted earlier, CCL3 represents EPA’s list  of the unregulated drinking water contaminants that may require  regulation because they are known or anticipated to occur in public water  systems. EPA had included n-propylbenzene and sec-butylbenzene in the  proposed list of UCMR3 contaminants, but it did not include them on the  final UCMR3. Instead, EPA included chromium-6, as well as total  chromium, which EPA stated became higher priorities for monitoring for  the agency. Public comments on the draft UCMR3 list also supported  monitoring these two contaminants. EPA’s Standards and Risk Reduction  Branch, which develops the regulatory determinations, supported the  inclusion of the two chromiums, as did a majority of the experts who  participated in our survey (35 of 40 supported adding chromium-6 and 28  of 40 supported adding total chromium). However, by including these two  higher priority contaminants, EPA removed two others in light of the cap  of 30 contaminants and could not take advantage of economies of scale  by using a method already selected for UCMR3 to obtain additional data.  In addition, MTBE could also have been monitored using the same  method. However, EPA officials told us they decided not to include  MTBE, which was monitored under UCMR1, because they did not need  additional information about it. As noted earlier, the priorities of EPA’s  Standards and Risk Reduction Branch are a key selection factor for which  contaminants to include on the UCMR. In the absence of the limit of 30,  EPA would have had an opportunity to monitor for these CCL3 chemicals,  as well as 1,1,1,2-Tetrachloroethane, as part of UCMR3 at nominal extra  cost. EPA officials told us that adding a contaminant to an ongoing  analysis typically costs about $5 to $10.
Similarly, our analysis indicates that eight contaminants of emerging  concern known as perfluorinated chemicals, or PFCs, could also have  been detected by the same analytical method that EPA is using to  monitor six other PFCs (see table 5). In 2009, EPA published an action  plan to address some of these chemicals, which the agency describes as  persistent in the environment and in people. This action plan also states  that it can reasonably be anticipated that continued exposure to PFCs  could harm human health. Due to industry’s increasing use of various  PFCs, EPA included six of the chemicals identified in this plan in UCMR3,  according to EPA officials. However, according to our analysis, five  additional PFCs from the plan are among the eight that could have been  detected using the same analytical method but are not on UCMR3. EPA  selected the six PFCs it thought most important, but the statutory limit of  30 contaminants curtailed EPA’s opportunity to gather occurrence data on  eight additional contaminants of emerging concern at little additional cost  or effort. EPA could have included the additional PFCs in UCMR3 but  doing so would have reduced the number of contaminants selected from  CCL3, EPA’s list of the unregulated drinking water contaminants that may  require regulation because they are known or anticipated to occur in  public water systems. Nonetheless, the agency will not have UCMR data  on whether or not those eight contaminants are present in the nation’s  drinking water until the next UCMR cycle at the very earliest; UCMR4  data collection is expected to be completed in 2021. However, EPA has  not decided which contaminants will be monitored under UCMR4, and so  it remains to be seen if they are included.
The legislative history of the SDWA Amendments of 1996 generally noted  concerns with the financial limitations of public water systems and their  abilities to absorb costs for activities such as monitoring. While the  number of contaminants being monitored is a factor, costs related to  analytical methods, such as laboratory equipment and labor, are key cost  drivers for UCMR monitoring, according to EPA officials. EPA officials told  us that they carefully consider the cost on public water systems when  selecting analytical methods for the UCMR program. In addition, EPA  pays for some of the small public water systems’ monitoring and must  stay within its budget for those costs. EPA documentation indicates that  UCMR3 will generally cost public water systems $50 to $470 per water  sample, per analytical method. EPA officials told us that the cost to detect  additional contaminants for an analytical method already in use was  nominal—typically about $5 to $10 per water sample, per contaminant.  Thus, the cost of adding contaminants to an analytical method that is  already being used would likely pose only a modest cost increase for  public water systems.
section_title: UCMR3 Excludes Previously Monitored Contaminants
paragraphs: One of EPA’s key selection factors for UCMR3 involved generally  eliminating contaminants that were monitored under a prior UCMR  round, but by eliminating those contaminants, EPA may encounter data  limitations because (1) the sampling methodology was not sufficient, (2)  the health information has been updated, or (3) the data have become  outdated.
Sampling methodology. One of the sampling methodologies EPA used in  a prior UCMR did not provide sufficient occurrence data to make  regulatory determinations for some contaminants, according to EPA’s  regulatory determinations for the CCL2 contaminants. Specifically,  UCMR1 used a limited sample size of 300 public water systems for the 14  contaminants it monitored using the screening survey approach. This  resulted in occurrence data for some contaminants that, according to EPA  documents, were not sufficient to make a national estimate. In its July  2008 Regulatory Determination notice, EPA found that a total of 12  contaminants monitored under UCMR1 had insufficient occurrence data  for making national estimates. Three of those contaminants are also listed  on CCL3—the pesticides disulfoton, diuron, and terbufos. By applying the  UCMR selection factor to eliminate contaminants monitored under  previous UCMR rounds, EPA did not consider remonitoring these  contaminants in UCMR3, even though EPA previously found the existing  data were not sufficient to make national estimates of contaminant  occurrence. However, 31 of the 40 experts who participated in our survey  said it would be worthwhile to monitor UCMR contaminants again if they  had insufficient data due to the sampling size.
According to EPA’s notice in the Federal Register for UCMR1, EPA’s  original intent was to use the screening survey as a first indicator of  potential contamination and then to remonitor the contaminants again  using assessment monitoring to obtain nationally representative results if  the contaminants occurred frequently enough in drinking water to warrant  doing so. However, EPA officials told us they later determined that this  approach was not feasible because of the time it required and did not  follow through with its plan to remonitor the UCMR1 contaminants. For  the UCMR2 and UCMR3 cycles, EPA revised its approach and increased  the screening survey sample size from 300 to 800. Specifically, under  UCMR1, the screening survey included a sample of 300 public water  systems. Under UCMR2 and UCMR3, the screening survey included a  sample of 800 public water systems and all of the systems serving more  than 100,000 people, for a total of approximately 1,200 systems. This  increase allowed EPA to make nationally representative estimates based  on the occurrence data.
Health effects information. According to EPA officials, health effects  information for unregulated contaminants is often uncertain and in flux  because research is often being conducted at the same time UCMR  monitoring is occurring. Those officials said the new research sometimes  indicates that health effects occur at lower levels of exposure than  previously thought. In recognition of this, EPA set the monitoring levels, or  MRLs, for UCMR3 based on how low the analytical method could reliably  measure specific contaminants, as reported earlier. However, EPA  previously set the MRLs for UCMR1 and UCMR2 with consideration of  the levels of public health concern that were known at the time. In May  2011, we reported that EPA set the MRLs for some of the UCMR1 and  UCMR2 contaminants before it had developed the health reference levels  for those contaminants. EPA subsequently determined that those MRLs  exceeded the health reference levels. As a result, occurrence of those  contaminants at a level higher than the health reference level but lower  than the MRL might not have been detected, and UCMR1 and UCMR2  occurrence data might not accurately capture the risk these contaminants  pose to public health. Similarly, if the health effects information about the  UCMR1 and UCMR2 contaminants changes in the future, EPA may not  have the data it needs to support regulatory determinations. Thirty-two of  the 40 experts who participated in our survey said it would be worthwhile  to monitor again for UCMR1 and UCMR2 contaminants if new health  effects information becomes available.
Age of data. The UCMR data estimated contaminant occurrence at the  time that they were collected. Due to changing industrial and agricultural  chemical use and environmental conditions, UCMR data may not present  an accurate picture of current contaminant occurrence after several  years. In particular, the UCMR1 data, which were collected from 2001 to  2003, are now over 10 years old. Nineteen of the 40 experts who  participated in our survey said that UCMR data this old are not likely to be  a reliable indicator of the frequency and level of drinking water  contamination, and 18 said they did not have enough information to judge  how long the UCMR data are likely to be a reliable indicator. EPA officials  and experts told us the shelf life of the UCMR data generally depends on  the type of contaminant and whether its use is likely to have changed  over time. According to the officials, concentrations of naturally occurring  contaminants remain relatively constant in drinking water over time but  concentrations of pesticides and industrial chemicals are subject to  change. While some of the UCMR1 data may still be a reliable indicator of  contaminant occurrence, several of the UCMR1 contaminants are  pesticides and industrial chemicals and the extent of their use has  changed since the UCMR data were collected. For example, use of the  pesticides disulfoton and molinate effectively ended following EPA actions  in 2009 and 2004, respectively. Use of the pesticides terbufos and  diuron also decreased significantly from 2003 to 2009, according to  USGS data. In addition, use of two industrial chemicals, MTBE and  nitrobenzene, decreased over time, according to EPA data. MTBE, a  former gasoline additive, has not been used in significant quantities since  2005. Nitrobenzene use has fluctuated over time but decreased sharply  from 1998 to 2005. Because the UCMR1 data estimate contamination at  a point in time prior to these changes, they likely overestimate current  levels of contaminant occurrence.
EPA might choose not to make regulatory determinations on some  contaminants if it concludes that the available occurrence data do not  provide sufficient support, as it did for several contaminants in 2008. As  we reported in May 2011, EPA did not make regulatory determinations for  some contaminants monitored under a prior UCMR round because the  occurrence data were not sufficient to do so. SDWA requires EPA to  use the best available data, but by not remonitoring contaminants when  appropriate, such as when the data collected in an earlier cycle have  become outdated, EPA may not have sufficient data to support its  regulatory determinations. SDWA does not prohibit EPA from  remonitoring UCMR contaminants; therefore, the agency has the option  to do so, for example when it believes that remonitoring would provide  better support for its regulatory determinations. EPA officials told us that  when developing future UCMRs, they will consider whether adequate  occurrence data for a contaminant had already been collected under a  prior UCMR, rather than generally eliminating all previously monitored  contaminants as part of its contaminants selection process. They also  said that if the officials who make the regulatory determinations asked for  a contaminant to be remonitored, they would consider doing so.
section_title: UCMR Data Support Regulatory Determinations, but Time Lag Results in Delays and Reliance on Older Data
paragraphs: EPA uses the UCMR data to support regulatory determinations but faces  a time lag when doing so. Agency officials told us UCMR data are EPA’s  primary source of data on the occurrence of unregulated contaminants in  drinking water and are a key input for regulatory determinations.  However, by the time the complete set of UCMR data is available, the  recurring 5-year deadline SDWA established for making at least 5  regulatory determinations has passed, leading EPA, in some cases, to  rely on older data that may no longer accurately reflect current  contaminant occurrence in drinking water.
subsections: section_title: UCMR Data Are EPA’s Primary Occurrence Data Source and a Key Input for Regulatory Determinations
paragraphs: EPA uses the UCMR data, along with information about the  contaminants’ health effects and other information, to make regulatory  determinations—that is, decisions on whether or not new primary drinking  water standards are needed for particular unregulated contaminants.  Regulatory determinations can be positive (i.e., a new primary standard is  needed) or negative (i.e., no new primary standard is needed). While  SDWA requires EPA to make regulatory determinations for at least five  CCL contaminants every 5 years, EPA officials told us their goal is to  make as many regulatory determinations as possible, given the available  data. EPA used UCMR1 data to support 9 of the 11 regulatory  determinations it made in 2008 for the CCL2 contaminants and another  regulatory determination in 2011. It is currently using UCMR1 and  UCMR2 data to inform its regulatory determinations for the CCL3  contaminants, which EPA expects to issue in 2015. The complete  UCMR3 data set will not be available until after those regulatory  determinations have been issued. However, if the timing allows, EPA  officials told us they may have an opportunity to use a partial UCMR3  data set to corroborate other data they have on contaminant occurrence  when making the final regulatory determinations.
EPA officials told us that, when they are available, UCMR data are EPA’s  primary data source on unregulated contaminants in drinking water  because they allow EPA to make national estimates of drinking water  contamination, as discussed earlier in this report. EPA also has data on  unregulated contaminants from other sources, such as USGS and some  states, but those data do not provide nationally representative estimates  of drinking water contamination. For example, the USGS data estimate  contamination in source water (i.e., untreated water from rivers, lakes,  and groundwater aquifers). Since source water can become public  drinking water, the USGS data can indicate potential drinking water  contamination. However, these data do not provide conclusive  information on whether contamination is occurring in public water  systems. EPA officials told us they use the other data to provide  additional support for regulatory determinations, but they generally do not  provide sufficient support on their own. In contrast, the UCMR data are  generally sufficient for estimating nationwide occurrence of drinking water  contamination, with the exceptions noted earlier in this report. In addition,  35 of the 40 experts who participated in our survey said that the UCMR  program has been an effective way to collect sufficient data to determine  whether contamination is occurring frequently and at levels of public  health concern in drinking water. Several experts provided additional  comments on the overall effectiveness of the UCMR program. For  example, one expert said that considering the great need for data and  EPA’s limited resources, the UCMR program has been one of the more  effective tools in the agency’s rule development process. Another expert  said that, given statutory requirements, resources, and data availability,  EPA has done an admirable job with the UCMR program. Finally, one  expert said that the UCMR program has been an effective way to remove  contaminants from the radar screen when they did not warrant regulation.
section_title: Time Lag Delays Regulatory Determinations by a Full 5-Year Cycle and Results in the Use of Older Data
paragraphs: A time lag between the SDWA deadline for regulatory determinations and  the UCMR data’s availability typically delays determinations on given  contaminants by a full 5-year cycle. SDWA sets deadlines for publishing  the CCL and UCMR contaminant list and making regulatory  determinations, but it does not set a deadline for monitoring the UCMR  contaminants. SDWA established recurring 5-year deadlines for making  regulatory determinations and for publishing the UCMR list. EPA has  established a 3-year monitoring period for the UCMR, but this overlaps  with the time frame during which EPA makes its regulatory  determinations. EPA also uses some older data that may no longer  accurately reflect current contaminant occurrence in drinking water when  it is making regulatory determinations.
subsections: section_title: Time Lag Typically Delays Regulatory Determinations for Contaminants by a Full 5-Year Cycle
paragraphs: A time lag between the statutory deadline for regulatory determinations  and the UCMR data’s availability typically delays regulatory  determinations on given contaminants until the following cycle. SDWA  directs EPA to publish a new CCL, UCMR, and set of regulatory  determinations every 5 years, as described earlier in this report. The  initial timeline staggered the deadlines such that EPA was required to  publish the UCMR list 18 months after the CCL and issue the regulatory  determinations 2 years after that. However, in practice, the 2-year window  SDWA set from the time EPA publishes the UCMR list to when it makes  regulatory determinations has not provided enough time for the agency to  monitor the contaminants and incorporate the UCMR data into the  determinations. Consequently, UCMR data are not available for EPA to  make regulatory determinations for contaminants during the cycle in  which they are monitored; rather, UCMR data for contaminants in one  cycle typically are not used until the next cycle or later (see fig. 4).
EPA officials told us that the timing of the UCMR program is a key  challenge, particularly in relation to the timing of the CCL and regulatory  determination deadlines. Since the UCMR program began, the full UCMR  data set has not been available until a year or more after EPA made its  regulatory determinations for the same 5-year cycle. The time lag is  influenced by the recurring 5-year deadlines for the CCL, UCMR, and  regulatory determinations and increased when EPA missed the deadlines  for CCL2 and UCMR2. As a result, UCMR2 data were not available until  nearly 3 years after EPA made the regulatory determinations for the  CCL2 contaminants. When EPA missed the UCMR2 deadline,  subsequent deadlines were moved to a later date, consistent with the 5- year cycle established by SDWA. Accordingly, the UCMR3 data will lag  behind the regulatory determinations for the CCL3 contaminants by over  a year. Based on EPA’s current schedules for the three programs, the  UCMR4 data will likewise lag behind the regulatory determinations for the  CCL4 contaminants. EPA’s schedule indicates that the agency plans to  make regulatory determinations for the CCL4 contaminants in spring  2020 and complete UCMR4 monitoring in December 2020, with the full  UCMR4 data set available in 2021. Without congressional action to make  the time frames more realistic, the time lag and resultant delays are  expected to continue in subsequent cycles.
section_title: Three-Year Monitoring Period Contributes to Time Lag
paragraphs: EPA has established a 3-year monitoring period for the UCMR, which  contributes to the time lag between the SDWA deadline for regulatory  determinations and the UCMR data’s availability. Before the monitoring  period begins, EPA spends about 1 year preparing for the monitoring that  public water systems will conduct. During this time, EPA finalizes the  monitoring schedules for systems that will be participating in the program  and approves the laboratories that will conduct the analyses, among other  things. Each public water system monitors for contaminants during a 12- month window throughout the 3-year period that follows. EPA officials told  us they spend up to 1 year finalizing the data collection and analysis,  which includes about 6 months for public water systems and laboratories  to report, review, and approve their data. The UCMR3 monitoring, data  collection, and analysis overlap with the time frame during which EPA will  be making its regulatory determinations for contaminants on CCL3.  UCMR3 monitoring is occurring from January 2013 through December  2015. Regulatory determinations for the CCL3 contaminants are expected  in spring 2015, according to agency officials. Officials who make the  regulatory determinations told us that it is helpful to have the UCMR data  about 2 years before publishing the final regulatory determinations. They  also told us they start using the data once about 70 percent of the data  set is available, approximately 2 years into the 3-year monitoring period.  For example, EPA began using the UCMR1 data set to inform its internal  deliberations on the regulatory determinations for CCL2 after about 70  percent of the data were available, according to agency officials. The  officials said that by this time in the data collection period they saw very  little variation in contaminant occurrence (i.e., the data were relatively  stable).
EPA officials told us they selected the 3-year monitoring period mainly for  logistical reasons impacting the agency and the public water systems.  They told us that the 3-year monitoring period spreads the agency’s work  out over a more manageable period of time. EPA staff provide technical  support to the public water systems conducting the monitoring, and many  also have other responsibilities, according to EPA officials. The 3-year  monitoring period also provides public water systems with more flexibility  to decide when they will start monitoring. EPA officials told us that, after  the agency publishes the final UCMR in the Federal Register, they assign  each system a month and year to start monitoring. However, some  systems request a later start date to incorporate the monitoring into their  budgets and operations, according to agency officials. EPA officials also  said laboratory capacity is sufficient under the 3-year period and has  approved 53 laboratories to participate in UCMR3. EPA officials had told  us that about 15 laboratories could probably handle the analytical work for  UCMR3, therefore, laboratory capacity may be sufficient under a shorter  monitoring period. Officials also told us that the 3-year monitoring period  is not a given. For example, officials told us that a 2-year monitoring  period, while challenging, may be possible for future cycles, but they  would have to evaluate the shorter time frame in detail to determine its  feasibility.
UCMR program officials also told us that monitoring over 3 years is  intended to allow them to account for the effects that extreme weather in  a given season could have on the data. They told us they did not know  whether a shorter monitoring period, such as a 2-year period, would also  allow them to do this because the extent of seasonal variability in the  UCMR program is unknown. However, they did not expect that a shorter  monitoring period would address variability to the same extent that the  current 3-year monitoring period would because the longer period of time  provides greater opportunity to detect it. Nonetheless, as reported earlier,  EPA officials who make the regulatory determinations observed very few  changes in occurrence trends after about 70 percent of the UCMR data  had been collected, about 2 years into the 3-year monitoring period.  When asked, experts who participated in our survey had mixed views on  whether a 2-year monitoring period would be likely to provide EPA with  sufficient information on seasonal fluctuations. Specifically, 19 of 40  respondents thought that it was likely to, 11 thought it was not likely to,  and 9 said they did not have enough information to judge. The UCMR3  data set may provide EPA with information that it can use to assess the  extent of seasonal variability, according to agency officials. Because  UCMR3 is monitoring for contaminants at low MRLs, it will likely have a  higher rate of detections than prior UCMRs and, therefore, more data  points that EPA can use to detect seasonal variability that it would have  missed in the past. EPA could use this information to help it understand  the extent of seasonal variability and the feasibility of a shorter monitoring  period.
section_title: EPA Uses Occurrence Data from Previous UCMR Cycles When Current Data Are Not Available
paragraphs: EPA has adapted to the time lag by using UCMR data from previous  cycles to make regulatory determinations. For example, EPA is using  UCMR1 and UCMR2 data to make regulatory determinations for the  CCL3 contaminants. Similarly, EPA used UCMR1 data to make  regulatory determinations for the CCL2 contaminants. Because EPA has  carried over many contaminants from one CCL to the next, officials told  us this is a workable approach. However, more than half of the experts  (25 of 40) who participated in our survey did not think using data from a  prior UCMR cycle was an effective strategy for making regulatory  determinations. Many of those experts were concerned because the time  lag delays regulatory determinations on given contaminants and leads  EPA to use older data that may not reflect current contaminant  occurrence in some cases. The time lag delays regulatory determinations  on contaminants by at least one 5-year cycle, and sometimes longer.  EPA officials told us that most of the UCMR3 data will be used to support  regulatory determinations for the CCL4 contaminants, which are expected  to be issued in 2020. Those UCMR3 contaminants that are carried over to  CCL4 will wait about 10 years for regulatory determinations unless EPA  uses data from another source or makes an out-of-cycle regulatory  determination (see fig. 5).
Regulatory determinations on given contaminants can also take longer to  make. For example, 11 of the contaminants EPA included on a short list  of potential regulatory determinations for CCL3 were first listed on CCL1  in March 1998. By the time EPA makes its regulatory determinations,  about 17 years will have passed since they were identified as  contaminants known or anticipated to occur in public water systems. In  addition, there are six contaminants that EPA carried over from CCL1 to  CCL3 that it has not yet included in a regulatory determinations cycle.  UCMR data are not yet available for any of them, although two—methyl  bromide and 1,1-dichloroethane—are currently being monitored under  UCMR3. Methyl bromide is a pesticide that was phased out of use in  2005; 1,1,-dichloroethane is an industrial chemical. Due to the time lag,  EPA’s first use of the UCMR3 data for these CCL1 contaminants will  likely be when it makes the regulatory determinations for CCL4. This is  about 22 years after they were first identified on the CCL as unregulated  contaminants that are known or anticipated to occur in public water  systems and may require regulation.
EPA is also using some older UCMR data that may not accurately reflect  current contaminant occurrence in drinking water to make regulatory  determinations, according to agency documents. Specifically, 6 of the 32  contaminants EPA included on its short list of potential regulatory  determinations for CCL3 were monitored from 2001 to 2003 under  UCMR1. EPA officials told us that one of the reasons the UCMR1 data  were not used for the regulatory determinations it issued in 2008 was  because health effects information on some of the contaminants was not  available. EPA’s July 2008 regulatory determinations indicate that there  were health effects information gaps for 3 of the 6 contaminants. As  noted earlier in the report, the UCMR1 data are now over 10 years old  and may not accurately reflect current levels of drinking water  contamination in some cases. In particular, the 6 UCMR1 contaminants  on EPA’s short list are industrial chemicals and pesticides, and the extent  of their use has changed since the UCMR data were collected, as  described earlier. Four of the 6 contaminants are pesticides: disulfoton,  molinate, terbufos, and diuron. The other 2 contaminants are industrial  chemicals: MTBE and nitrobenzene. Further, in its July 2008 Regulatory  Determination notice, EPA stated that it had insufficient occurrence data  for making national estimates of disulfoton, diuron, and terbufos  contamination. Occurrence data had been collected on those  contaminants under UCMR1 but, as discussed earlier in this report, the  sampling methodology used was not sufficient. EPA has not collected  new occurrence data on the contaminants since then. As a result, the  older data may not provide an accurate basis for EPA to use when  making regulatory determinations.
section_title: Conclusions
paragraphs: The overall goal of SDWA is to ensure that public drinking water is safe.  The UCMR program is an important component of EPA’s implementation  of the act. As EPA’s primary data source for assessing the nation’s  potential exposure to unregulated contaminants and the levels of that  exposure, the UCMR plays a key role in EPA’s regulatory development  process. As a result, the accuracy and timeliness of the data it provides  are important to support informed decision making. The technical  changes EPA has made to UCMR3 in response to our 2011  recommendations are significant improvements over prior UCMR cycles.  First, by more fully utilizing its statutory authority and monitoring for 30  contaminants under UCMR3, EPA has increased the productivity of the  UCMR program. As a result, more data will be available to inform  regulatory determinations in the future. Second, by increasing the sample  size of the public water systems monitoring under the screening survey  approach, EPA has also increased the statistical strength of its monitoring  results. The larger sample size should allow EPA to make better  estimates of exposure to drinking water contaminants. Third, by  monitoring for contaminants at lower detection levels, or MRLs, the  UCMR3 data are more likely to remain useful even in light of new  information about the contaminants’ health effects in the future.
However, some statutory provisions pose limitations for obtaining  additional and more timely data. First, because SDWA caps the number  of UCMR contaminants in each 5-year cycle at 30, the agency is not able  to take advantage of economies of scale by collecting occurrence data on  additional contaminants. As a result, EPA does not have the opportunity  to collect data on additional unregulated contaminants at little additional  effort and cost to the agency or the public water systems. The cost to  detect additional contaminants with analytical methods already being  used by the UCMR program can be nominal. Second, the 2-year window  SDWA initially established from the time EPA publishes the UCMR list to  when it publishes the regulatory determinations does not provide  adequate time for the UCMR data to support regulatory determinations in  the same cycle. As a practical matter, the time frames SDWA initially  established are not adequate to provide enough time for UCMR’s data  collection period and EPA’s subsequent use of the data. As a result,  regulatory determinations on given contaminants are typically delayed by  a full 5-year cycle, meaning that about 10 years pass from when EPA  identifies them on the CCL as potential problems and decides whether  they need to be regulated. Two contaminants—methyl bromide and 1,1- dichloroethane—will likely wait 22 years after their initial listing for  regulatory determinations. Without congressional action to make the  statutory time frames more realistic, the time lag and resultant delays are  expected to continue in subsequent cycles.
The UCMR program faces other limitations that may cause EPA to base  its regulatory determinations on inaccurate or outdated information. In  particular, EPA’s standard monitoring frequency may not be accurately  estimating the occurrence of certain contaminants in the public’s drinking  water, particularly those that occur sporadically like viruses or seasonally  like pesticides. By not varying the monitoring frequency for contaminants  when appropriate, for example by increasing the frequency during the  months when EPA expects viruses to be present, the UCMR data may  not provide reliable estimates of contaminant occurrence. Similarly, by not  remonitoring contaminants from prior UCMR cycles when appropriate,  EPA may not have sufficient data to support its regulatory determinations.  EPA continues to use data from past UCMR cycles to inform its  regulatory determinations, but those data sets have potential limitations.  For example, EPA previously determined that some of the data collected  under UCMR1 were not sufficient to make national estimates of  contaminant occurrence. Because EPA has not remonitored those  contaminants, the agency still does not have sufficient UCMR data about  them. Similarly, some of the UCMR1 data may be outdated due to  changing industrial and agricultural chemical use and environmental  conditions. As a result, the existing UCMR data for certain contaminants  may no longer accurately reflect current drinking water conditions. We are  encouraged by recent statements from EPA officials indicating that they  will consider whether adequate occurrence data for a contaminant had  already been collected under a prior UCMR when selecting contaminants  in the future. Finally, the timing of the UCMR program significantly  reduces the availability of the data to support regulatory determinations.  Specifically, the time lines for the contaminant selection process and  monitoring period do not get the UCMR data into the hands of EPA  officials in time to support regulatory determinations in the same cycle.  The UCMR data are EPA’s preferred source of information on  contaminant occurrence because the program has been specifically  designed to yield nationally representative estimates of drinking water  contamination. However, if the UCMR data are not available, EPA either  must use data from another source, or delay making regulatory  determinations on specific contaminants. For most of the UCMR3  contaminants, over 10 years are likely to pass between the time that EPA  first listed contaminants on CCL3 in 2009 and the time that regulatory  determinations are made for those contaminants, expected in 2020. The  SDWA deadlines, EPA’s lengthy contaminant selection process, and its  3-year monitoring period all contribute to the time lag. As stated earlier, to  change the statutory deadlines and adjust the time frames requires  congressional action, and shortening the selection process and  monitoring period requires EPA action. UCMR program officials  coordinate closely with the other two EPA offices that make regulatory  determinations and develop the CCL and are sensitive to the impact that  timeliness has on each of these processes. We recognize that EPA  officials must consider a variety of data quality objectives, logistical  needs, and the burden on public water systems in managing the UCMR  program, regulatory determinations, and CCL. But, since EPA officials  consider the UCMR data to be their primary source of occurrence data for  the regulatory determinations, it is important that these data also be  timely. However, without a coordinated effort to address the time lag,  most contaminants on the CCL will continue to wait 10 years or longer for  a regulatory determination.
section_title: Matters for Congressional Consideration
paragraphs: To take advantage of opportunities to collect UCMR data on additional  unregulated contaminants, Congress should consider amending  SDWA to give EPA the flexibility to select more than 30 contaminants  for monitoring under the UCMR program if high-priority contaminants,  such as those on the CCL or contaminants of emerging concern, can  be included at minimal cost, with minimal additional burden on public  water systems, and while using analytical methods that EPA is  already employing.
To optimize the ability of the UCMR data to support regulatory  determinations, Congress should consider adjusting the statutory time  frames for the UCMR and regulatory determinations cycles so that  EPA can use the UCMR data to support regulatory determinations in  the same cycle.
section_title: Recommendations for Executive Action
paragraphs: We recommend that the Administrator of the Environmental Protection  Agency direct the Assistant Administrator of the Office of Water to take  the following three actions:
To help ensure that the UCMR data accurately reflect contaminant  occurrence, vary the monitoring frequency for public water systems  when the standard UCMR monitoring frequency is not expected to  accurately detect the presence of contaminants, such as sporadically  occurring viruses or pesticides that fluctuate seasonally.
To help address potential limitations with the UCMR data, when  considering if adequate data had been collected under a prior UCMR  during the contaminant selection process, take into account whether: the sampling methodology EPA used in a prior UCMR for a  particular contaminant provided sufficient occurrence data to  make a regulatory determination,  the contaminant’s health information is in flux or has been updated  and now indicates that adverse health effects occur at a lower  level than that at which UCMR data were originally collected, or  the data collected in an earlier cycle have become outdated and  no longer present an accurate picture of contaminant occurrence,  for example, because industrial or agricultural chemical use has  changed.
To optimize the ability of the UCMR program to support regulatory  determinations, convene an internal working group of officials  responsible for the UCMR, regulatory determinations, and CCL to fully  examine opportunities to improve the timeliness of the UCMR  program. Among other things, the working group should consider: whether a shorter process for selecting contaminants would yield  a high-quality list, or whether the existing process can be started  sooner, and whether monitoring for contaminants over a shorter period,  instead of the current 3-year period, is feasible, given data quality,  logistical needs, and the burden on public water systems.
section_title: Agency Comments
paragraphs: We provided EPA with a draft of this report for its review and comment. In  written comments, reproduced in appendix VI, EPA generally agreed with  our findings and conclusions and is committed to implementing our  recommendations when it develops the next UCMR.
EPA also provided technical comments, which we incorporated as  appropriate.
As agreed with your offices, unless you publically announce the contents  of this report earlier, we plan no further distribution until 30 days from the  report date. At that time, we will send copies of this report to the  Administrator of EPA and the appropriate congressional committees. In  addition, this report will be available at no charge on the GAO website at  http://www.gao.gov.
If you or your staff members have any questions about this report, please  contact me at (202) 512-3841or gomezj@gao.gov. Contact points for our  Offices of Congressional Relations and Public Affairs may be found on  the last page of this report. GAO staff who made key contributions to the  report are listed in appendix VII.
section_title: Appendix I: Objectives, Scope, and Methodology
paragraphs: This report addressed the following objectives (1) evaluate the extent to  which the Environmental Protection Agency (EPA) implemented the  recommendations GAO made in 2011 to improve the Unregulated  Contaminant Monitoring Rule (UCMR) program and any opportunities that  may exist to strengthen it further; (2) identify the factors EPA considered  when it selected the contaminants for monitoring under UCMR3 and the  limitations, if any, that EPA faced in selecting the contaminants; and (3)  examine the extent to which UCMR data support EPA’s regulatory  determinations.
To obtain information for each of our objectives on issues related to  monitoring unregulated drinking water contaminants, we surveyed a  broad range of experts in two rounds using the Delphi method. The  Delphi method consists of surveying experts in two or more rounds to  obtain group agreement or consensus on key topics. For this report, the  first round of the survey was comprised of open-ended questions that  asked experts to provide their views on the strengths and weaknesses of  EPA’s UCMR program, as well as suggestions for improving the program.  The second round included primarily closed-ended questions developed  from our content analysis of the first round survey responses. To identify  experts for the first round of the survey, we reviewed public comments  provided on EPA’s proposed rules for its Contaminant Candidate Lists  (CCL), UCMR, and preliminary regulatory determinations. We also  reviewed public nominations of drinking water contaminants submitted to  EPA and EPA documentation on two expert panels it convened to provide  input and review of chemical and microbial contaminants for CCL3. We  identified 14 experts from academia, an analytical laboratory,  environmental advocacy organizations, professional associations, water  utilities, and federal and state government agencies. These experts were  selected based on their demonstrated familiarity with EPA’s CCL, UCMR,  and regulatory determination processes. The first round of the survey— which ran from December 12, 2012 to January 4, 2013—asked these  experts to respond to 10 open-ended questions. These questions asked  about various aspects of the UCMR program that helped or hindered EPA  in (1) selecting priority contaminants, (2) monitoring for selected  contaminants, and (3) using the data to support regulatory  determinations. We also asked the experts whether programmatic or  statutory changes were needed to address any challenges identified. We  received responses from 14 of the 14 experts we surveyed in the first  round of the survey.
We performed a content analysis of the responses from the first round of  the survey to identify the most important issues raised by the experts. We  used the results of the content analysis to develop questions for the  second round of the survey. Because this was not a sample survey, it had  no sampling errors. However, the practical difficulties of conducting any  survey can introduce nonsampling errors, such as difficulties interpreting  a particular question, which can introduce unwanted variability into the  survey results. We took steps to minimize nonsampling errors by  pretesting the questionnaire with five experts. This helped ensure that the  questions were clear and unbiased, and that the questionnaire did not  place an undue burden on respondents. An independent reviewer within  GAO also reviewed a draft of the questionnaire prior to its administration.  We made appropriate revisions to the content and format of the second  round survey questionnaire based on the pretests and independent  review.
To identify experts for the second round of the survey, we developed a  preliminary list of experts, which included the 14 experts who completed  the first round of the survey and others identified through interviews with  stakeholders and our review of public comments provided on EPA’s  proposed rules. We contracted with the National Academy of Sciences to  identify additional experts. We selected 48 experts for the second round  of the survey based on their knowledge of one or more of the following  topic areas: drinking water, contaminant monitoring, analytical methods,  toxicology, risk assessment, and environmental regulation. Similar to the  first round of the survey, the selected experts were from academia,  analytical laboratories, environmental advocacy organizations, industry,  water utilities, and federal and state government agencies. The second  round of the survey was administered on the Internet from May 10, 2013  to June 7, 2013. Experts were sent an e-mail invitation to complete the  survey on a GAO web server using a unique username and password. To  increase the response rate, we followed up with e-mails and personal  phone calls to the experts to encourage participation in our survey. The  second round of the survey had an 83 percent response rate. We  received responses from 40 of 48 experts, including 12 who had also  completed round one of the survey. The information that we obtained  from the expert survey is not generalizable to all experts that have an  interest in or knowledge of drinking water contaminant monitoring issues.  The full survey and responses are available in appendix IV. The survey  participants are listed in appendix V.
To evaluate the extent to which EPA implemented GAO’s May 2011  recommendations to improve the UCMR program, we reviewed EPA’s  proposed and final rules for the UCMR program and interviewed the  relevant EPA officials who are responsible for designing and  implementing the UCMR program to identify specific actions the agency  had taken. To identify any opportunities that may exist to strengthen the  UCMR program further, we interviewed stakeholders to obtain their  perspectives on the UCMR program and related issues. In addition, we  assessed EPA’s sampling methodology against standard statistical  criteria to determine whether the resulting sample sizes are likely to  provide EPA with sufficient data for making national estimates of  contaminant occurrence and exposure within an acceptable margin of  error.
To identify the factors EPA considered when it selected the contaminants  for monitoring under UCMR3, we reviewed EPA documentation  describing the steps the agency took to select the contaminants, including  UCMR3 working group meeting minutes and EPA’s proposed and final  rules for the UCMR program and the CCL, which serves as EPA’s  primary basis for selecting UCMR contaminants. We also interviewed  EPA officials who are responsible for designing and implementing the  UCMR program, including selecting the UCMR contaminants; as well as  those responsible for developing the CCL and making regulatory  determinations. To identify the limitations, if any, EPA faced in selecting  the contaminants, we interviewed stakeholders to obtain their  perspectives on the UCMR contaminant selection process and related  issues. In addition, we assessed the UCMR contaminant selection  process against statutory requirements.
To examine the extent to which UCMR data support EPA’s regulatory  determinations, we reviewed EPA and Federal Register documents about  the use of the data for making the CCL2 and CCL3 regulatory  determinations. In addition, we interviewed EPA officials who are  responsible for designing and implementing the UCMR program and for  making regulatory determinations. We also considered the time frames  for implementing the UCMR program and using UCMR data for making  regulatory determinations and assessed them against statutory  requirements and GAO criteria for program timeliness. There is broad  recognition throughout the federal government that, in addition to being  effective in producing desired outcomes and other important dimensions  of performance, agencies need to operate programs and provide  information about them in a timely and efficient manner. For example, the  GPRA Modernization Act calls on agencies to set goals and measure  their progress toward meeting them. Timeliness is an important  dimension of program performance. In addition, EPA initiated a new  drinking water strategy in 2010 that recognizes the need to improve the  timeliness of its efforts to address unregulated contaminants.
We conducted this performance audit from June 2012 to January 2014 in  accordance with generally accepted government auditing standards.  Those standards require that we plan and perform the audit to obtain  sufficient, appropriate evidence to provide a reasonable basis for our  findings and conclusions based on our audit objectives. We believe that  the evidence obtained provides a reasonable basis for our findings and  conclusions based on our audit objectives.
section_title: Appendix II: UCMR3 Contaminants
paragraphs: Appendix II: UCMR3 Contaminants 1,4-dioxane  molybdenum  cobalt  1,2,3-trichloropropane  1,3-butadiene  chloromethane (methyl chloride)  1,1-dichloroethane  bromochloromethane (Halon 1011)  bromomethane (methyl bromide)  chlorodifluoromethane (HCFC-22)
section_title: Appendix III: Information on Analytical Methods
paragraphs: Analytical methods are laboratory tests that measure the level of chemical  and microbial contamination in a sample of drinking water. Analytical  methods specify the volume of the sample to be tested, laboratory  equipment and procedure used to test the sample, and quality control  procedures to ensure the test is run correctly. Analytical methods vary  based on the type of contaminant; different equipment and techniques are  required for analyzing chemicals versus microbes. For example,  laboratories use specialized scientific equipment such as gas  chromatograph-mass spectrometers (GC-MS) to detect the presence of  some chemicals in drinking water.
Because the Unregulated Contaminant Monitoring Rule (UCMR) collects  nationwide data, the Environmental Protection Agency’s (EPA) goal is to  use analytical methods that offer consistent application across the  country. To get the data quality and accuracy that EPA needs, the agency  uses analytical methods for UCMR that, among other requirements (1)  have sufficient “holding times” for shipment of water samples from water  utilities to laboratories; (2) can be used by a variety of laboratories with  varying levels of expertise; and (3) can be used equally effectively under  different drinking water conditions and types. EPA often develops  analytical methods for the UCMR program that meet these specific  requirements. When EPA develops an analytical method, there are many  key steps it follows. EPA begins with optimizing instrumentation and  determining the best calibration, which involves setting up the equipment  to measure a contaminant at the desired level. Next, EPA staff optimize  the solid phase extraction—a process that involves separating  compounds that are dissolved or suspended in water from other  compounds in the water sample according to their physical and chemical  properties in order to isolate the contaminant for analysis. Then, EPA staff  determine which preservatives to use that will allow the chemical to be  preserved in the water sample. They also determine any interferences– if  there are other chemicals or substances in the water sample that may  have similar physical and chemical properties and thus interfere with the  chemical to be analyzed—and how to address such interferences, if any.  Then, EPA staff determine the holding times for the contaminant and the  water sample; as noted earlier, EPA must have sufficient “holding times”  for shipment of water samples from water utilities to laboratories. These  holding times must not have any negative impact in quality on the  contaminant to be analyzed in the water sample. After following all these  steps, if the analytical method meets EPA’s data quality objectives, then  EPA writes the method so that laboratories across the country can use  and follow the EPA instructions to measure the level of contamination in  drinking water. EPA then sends the written analytical method to several  laboratories to ensure the method works as written; this process is known  as a multilab verification process. If the method passes this verification  process, then EPA publishes and uses the analytical method in a future  UCMR. On the other hand, if the analytical method does not meet the  data quality objectives that EPA has set, EPA revises the technical  approach in order for the earlier steps in the analysis to lead to a method  that meets the data quality objectives. See figure 6.
Developing an analytical method can be a complex, technically  challenging, and time-consuming process. For example, EPA officials  cited challenges for developing methods for some CCL3 contaminants  such as the high water solubility of some contaminants, as well as some  contaminants’ instability in water. In such cases, EPA cannot keep these  contaminants stable in the water samples for the minimum holding times  that are required between the collection of samples by public water  systems and sending the samples to the laboratories for analysis. For  these contaminants, EPA is still working on techniques that will allow the  agency to develop an analytical method that works effectively under all  the conditions noted above that UCMR analytical methods must meet.  EPA officials said it can take 1 to 2 years to develop a standard method  that meets their data quality requirements and 2 to 3 years for more  complex methods.
Most often, the UCMR program uses EPA analytical methods, but it also  allowed some methods developed by others as alternatives for UCMR3.  EPA is also using compliance methods in the UCMR3 program.  Compliance methods are analytical methods that laboratories are  required to use when monitoring for regulated drinking water  contaminants. For example, the analytical method for volatile organic  compounds that EPA is using for UCMR3 is a compliance method. In  addition, EPA involves stakeholders in its development of analytical  methods. In May 2013, EPA held a public meeting and webinar to provide  stakeholders with an update on analytical methods completed or under  development for potential use in the UCMR program. Several external  stakeholders participated in the meeting, both in person and via webinar.  Some of them provided suggestions to address challenges EPA was  facing with certain methods.
section_title: Appendix IV: Round 2 Survey Questionnaire and Results
paragraphs: The questions we asked experts in Round 2 of our survey are shown  below. Our survey was composed of closed- and open-ended questions.  In this appendix, we include all the survey questions and aggregate  results of responses to the closed-ended questions; we do not provide  information on responses provided to the open-ended questions. For a  more detailed discussion of our survey methodology, see appendix I. For  a list of the experts who completed our survey, see appendix V.
Survey on EPA's Unregulated Contaminant Monitoring Program   EPA uses the Unregulated Contaminant Monitoring Rule (UCMR) program to collect data for some  contaminants that are suspected to be present in drinking water, but do not have health-based standards set  under the Safe Drinking Water Act. Under the Safe Drinking Water Act, EPA is responsible for identifying and  regulating drinking water contaminants that may pose a public health risk. Specifically, the act directs EPA to:   1. Publish a list every 5 years of contaminants that are a) not currently regulated b) known or anticipated to  occur in public water systems and c) may require regulation. EPA has implemented this provision as the  Contaminant Candidate List.   2. Establish a program to monitor unregulated contaminants and publish a list every 5 years of up to 30  contaminants to be monitored by public water systems. EPA has implemented this provision as the  Unregulated Contaminant Monitoring Rule (UCMR) program.   3. Determine whether or not to regulate at least 5 contaminants included on the list of unregulated  contaminants every 5 years. EPA has implemented this provision as the regulatory determination process. The  act specifies that EPA shall regulate a drinking water contaminant under certain conditions. To see these  conditions, click here. [In the online-version of the survey, this was a live link to the Safe Drinking Water Act  requirements for making a regulatory determination.]  Some of the contaminants on the Contaminant Candidate List are monitored under the UCMR. EPA uses the  monitoring data, along with information about the contaminants' health effects, to determine whether or not to  regulate the contaminants. EPA is currently in its third round of the UCMR program (UCMR-3).
EPA is monitoring 30 contaminants under UCMR-3. Click here to review the list. [In the online-version of the  survey this was a live link. See appendix II of this report for a list of the 30 contaminants.]     --------------------------------------------------------------------------------  Section 1: UCMR Program Requirements and Considerations  The Safe Drinking Water Act requires that EPA publish a list of unregulated contaminants that pose the  greatest public health concern, are known or anticipated to occur in public water systems, and may require  regulation. This is known as the Contaminant Candidate List (CCL).    1.  EPA uses the Unregulated Contaminant Monitoring Rule (UCMR) program to collect monitoring data for  informing its regulatory determinations about some of the contaminants on the CCL. The Safe Drinking Water  Act requires EPA to select contaminants that pose the greatest public health concern for its CCL and for  regulatory determinations.
subsections: section_title: Was CCL-3 a reasonable source for EPA to use when it began identifying contaminants for the UCMR-3?
section_title: If EPA combined the CCL and UCMR contaminant selection processes, would the resulting UCMR list likely be of similar or better quality when compared to the UCMR list created under the current separate processes?
section_title: Do the 30 contaminants EPA selected warrant being included in UCMR-3? Click here to review the list. [In the online-version of the survey this was a live link. See appendix II of this report for a list of the 30 contaminants.]
paragraphs: 5-Not enough information to judge  7.  EPA added chromium-6 and total chromium to the UCMR-3 list based largely on the strength of public  comments supporting these additions.    7A.  Did chromium-6 warrant being included on the UCMR-3 list?    5-Not enough information to judge  7B.  Did total chromium warrant being included on the UCMR-3 list?    5-Not enough information to judge  --------------------------------------------------------------------------------  Section 2: Factors EPA Considers when Selecting Contaminants for UCMR  8.  One factor EPA considers when selecting contaminants for UCMR is what health effects information is  available for the universe of unregulated contaminants.
In general, was enough health effects information available when EPA began selecting contaminants in 2009  to identify contaminants that potentially pose the greatest public health concern?    5-Not enough information to judge  9.  EPA also needs health effects information when determining whether or not to regulate a contaminant  monitored under UCMR. However, health effects information is often being developed for contaminants at the  same time that the UCMR program is collecting data about contaminant occurrence.
Given this situation, is it worthwhile for EPA to select contaminants for UCMR when the health effects  information needed to make regulatory determinations is not yet available?    10.  Another factor EPA considers when selecting contaminants for UCMR is whether or not the contaminant  was included in a prior round of UCMR. EPA typically does not select contaminants that were previously  included. While this policy reduces the burden on public water systems, there have been situations in which  monitoring again could enable EPA to collect better data. The following questions ask about such situations.    10A.  In the first round of the UCMR program, the sampling methodology that EPA used to select water  systems had limitations, and therefore the program did not provide sufficient data for making decisions about  whether or not to regulate some of the contaminants.
Given the tradeoff between burden on water systems and data quality, would it be worthwhile for EPA to  consider selecting some of those contaminants again for monitoring under UCMR?    5-Not enough information to judge  10B.  In prior rounds of the UCMR program, some of the analytical methods used were not sensitive enough to  detect contaminants at EPA's health effects benchmark. More sensitive analytical methods have since become  available for some of these contaminants.
Given the tradeoff between burden on water systems and data quality, would it be worthwhile for EPA to  consider selecting some of those contaminants again for monitoring under UCMR?    5-Not enough information to judge  10C.  New or updated health effects information is now available for some contaminants monitored in prior  rounds of the UCMR. The new information indicates that health effects occur at lower concentrations than  those previously monitored for.
Given the tradeoff between burden on water systems and data quality, would it be worthwhile for EPA to  consider selecting some of those contaminants again for monitoring under UCMR?    5-Not enough information to judge  11.  Another factor EPA considers when selecting contaminants for UCMR is whether analytical methods will  be available to detect these contaminants in drinking water. EPA typically develops analytical methods for the  contaminants it plans to monitor. For UCMR-3, EPA also considered analytical methods that had been  developed by Standard Methods and the American Society for Testing and Materials.
For future rounds of UCMR, will it be worthwhile for EPA to reach out to organizations that develop such  analytical methods before it selects contaminants?    12.  Another factor EPA considers when selecting contaminants for UCMR is whether the contaminants are  similar to others it will be monitoring. EPA selected 6 contaminants for UCMR-3 primarily because they could  be detected by an analytical method that will be used for another UCMR-3 contaminant. These 6 were not on  the CCL-3, EPA's primary source for selecting UCMR-3 contaminants.
Is it worthwhile for EPA to select contaminants for the UCMR primarily because they can be detected by an  analytical method that will be used for another UCMR contaminant?    13.  Another factor EPA considers when selecting contaminants is stakeholder input. For UCMR-3, EPA  convened a State working group, held a public stakeholder meeting, and collected public comments on the  proposed rule published in the Federal Register.
Did these means of communication give stakeholders enough opportunity to provide input on the contaminants  that EPA selected for UCMR-3?    5-Not enough information to judge  14.  When EPA develops the CCL it is reviewed by EPA's Science Advisory Board. In addition, EPA solicited  additional expert input from the National Drinking Water Advisory Board and from other outside experts when it  selected contaminants for the CCL-3.
Should EPA use similar means to obtain additional expert input when it selects contaminants for the UCMR?    15.  In addition to EPA, the US Geological Survey, some states, and other groups generate contaminant  occurrence data. EPA reviews some of this other data when selecting the UCMR contaminants.
Is it worthwhile for EPA to consider this other data on contaminant occurrence when it selects contaminants for  UCMR?    --------------------------------------------------------------------------------  Section 3: Collection of Contaminant Occurrence Data through the UCMR Program  16.  EPA varies the frequency for monitoring based primarily on the source water type. Under UCMR-3,  surface water systems must monitor for 4 consecutive quarters with sampling events 3 months apart.
Is the requirement that surface water systems monitor for 4 consecutive quarters likely to provide EPA  sufficient data to determine whether contaminants occur with a frequency and at levels of public health  concern?    5-Not enough information to judge  Please explain your answer to question 16:    17.  Under UCMR-3, ground water systems must monitor twice in a 12-month period with sampling events 5- 7 months apart.
Is the requirement that ground water systems monitor twice in a 12-month period likely to provide EPA  sufficient data to determine whether contaminants occur with a frequency and at levels of public health  concern?
Please explain your answer to question 17:    18.  Under UCMR-3, non-disinfecting ground water systems located in sensitive hydrogeological areas (i.e.,  karst or fractured bedrock) must monitor twice in a 12-month period with sampling events 5-7 months apart for  2 viruses.
section_title: 19B. For the 30 contaminants being monitored under UCMR-3, would a 2-year monitoring timeframe instead of the 3-year timeframe be likely to provide EPA sufficient information on seasonal fluctuations in contaminant occurrence?
section_title: Is Tier I monitoring likely to provide EPA sufficient data to determine whether contaminants occur with a frequency and at levels of public health concern?
section_title: Is Tier II monitoring likely to provide EPA sufficient data to determine whether contaminants occur with a frequency and at levels of public health concern?
section_title: Is Tier III monitoring likely to provide EPA sufficient data to determine whether contaminants occur with a frequency and at levels of public health concern?
section_title: 5-Not enough information to judge
section_title: 23. Overall, is the three-tiered monitoring strategy described in questions 20-22, which varies the number and size of water systems based on the availability of analytical methods, likely to provide EPA sufficient data to determine whether contaminants occur with a frequency and at levels of public health concern?
section_title: Is this type of monitoring likely to help EPA better understand the co-occurrence of pathogen indicators and viruses?
section_title: 5-Not enough information to judge
section_title: 25A. Is this type of monitoring likely to provide EPA with valuable information on the co-occurrence of total chromium and chromium-6?
section_title: 25B. Is this type of monitoring likely to provide EPA with valuable information on the usefulness of monitoring for total chromium as an indicator for chromium-6?
section_title: 5-Not enough information to judge
paragraphs: --------------------------------------------------------------------------------  Section 4: Use of the UCMR Contaminant Occurrence Data   26.  EPA uses UCMR data to make regulatory determinations for some of the contaminants listed on the CCL.  Due to a time lag, the UCMR-3 occurrence data will not be available to inform the regulatory determinations  about the contaminants on CCL-3. As a result, EPA is using occurrence data from prior UCMRs to inform  these regulatory determinations. CCL-3 includes 28 contaminants monitored under prior UCMRs.
Is this likely to be an effective strategy for making regulatory determinations, given the time lag?    5-Not enough information to judge  Please explain your answer to question 26:    27.  Sometimes EPA waits several years before it uses the UCMR occurrence data to inform its regulatory  determinations.
After the UCMR occurrence data has been collected, about how long is it likely to be a reliable indicator of the  frequency and level of drinking water contamination?    c.-5 to less than 11 years  d.-11 to less than 16 years  e.-16 to less than 20 years  g.-Not enough information to judge  28.  The primary purpose of the UCMR program is to collect contaminant occurrence data for informing  regulatory determinations which are based, in part, on the frequency and level of drinking water contamination.
Overall, how effective has the UCMR program been at collecting sufficient data to determine whether  contaminants occur with a frequency and at levels of public health concern?    4-Not enough information to judge  29.  Another purpose of the UCMR program is to inform EPA's development of future CCLs. EPA expects to  complete its data collection and analysis for UCMR-3 in 2016; it expects to finalize its next CCL in 2014.
Given the tradeoff between data completeness and timeliness, would it be worthwhile for EPA to use partial  UCMR data to inform its next CCL?    30.  An additional purpose of the UCMR program is to inform EPA's health research planning. For example,  EPA might prioritize the completion of health effects information for a specific contaminant over others if it  believes the contaminant is likely to be found in drinking water. EPA expects to complete its data collection and  analysis for UCMR-3 in 2016; its health research planning is on-going.
Given the tradeoff between data completeness and timeliness, would it be worthwhile for EPA to use partial  UCMR data to inform its health research planning?    5-Not enough information to judge  IMPORTANT: Please continue to the next screen to submit your final responses to GAO.    --------------------------------------------------------------------------------  Submit Your Final Responses to GAO  31.  Are you ready to submit your final completed survey to GAO?   (This is equivalent to mailing a completed paper survey to us. It tells us that your answers are official and final.)
section_title: Appendix V: List of Experts Who Completed the Surveys
section_title: Appendix VI: Comments from the Environmental Protection Agency
section_title: Appendix VII: GAO Contact and Staff Acknowledgments
subsections: section_title: GAO Contact
section_title: Staff Acknowledgments
paragraphs: In addition to the individual named above, Diane B. Raynes (Assistant  Director), Elizabeth Beardsley, Mark Braza, Justin Fisher, Annamarie  Lopata, Rebecca Makar, Christopher Murray, Alison O’Neill, Dan Royer,  Kelly Rubin, and Esther Toledo made significant contributions to this  report.
section_title: Related GAO Products
paragraphs: Chemical Assessments: An Agencywide Strategy May Help EPA Address  Unmet Needs for Integrated Risk Information System Assessments.  GAO-13-369. Washington, D.C.: May 10, 2013.
Environmental Health: Action Needed to Sustain Agencies’ Collaboration  on Pharmaceuticals in Drinking Water. GAO-11-346. Washington, D.C.:  August 8, 2011.
Safe Drinking Water Act: Improvements in Implementation Are Needed to  Better Assure the Public of Safe Drinking Water. GAO-11-803T.  Washington, D.C.: July 12, 2011.
Safe Drinking Water Act: EPA Should Improve Implementation of  Requirements on Whether to Regulate Additional Contaminants.  GAO-11-254. Washington, D.C.: May, 27, 2011.
Perchlorate: Occurrence is Widespread but at Varying Levels; Federal  Agencies Have Taken Some Actions to Respond to and Lessen  Releases. GAO-10-769. Washington, D.C.: August 12, 2010.
Safe Drinking Water Act: Progress and Future Challenges in  Implementing the 1996 Amendments. GAO/RCED-99-31. Washington,  D.C.: January 14, 1999.