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Drinking Water Distribution Systems: Assessing and Reducing Risks 2 Regulations, Non-regulatory Approaches, and their Limitations This chapter provides an overview of the existing regulatory framework as well as non-regulatory approaches that are intended to protect drinking water quality within water distribution systems. Included is a discussion of federal and state statutes and regulations and local codes, along with their limitations. In addition, several non-regulatory programs are described that are intended to complement existing regulations. REGULATORY ENVIRONMENT Federal and state statutes and regulations along with local codes are used to establish requirements intended to protect the drinking water quality within distribution systems. The federal Safe Drinking Water Act (SDWA) is the vehicle used nationally to address drinking water quality issues. Prior to the passage of the SDWA, federal involvement in water supply had been limited to development of large multi-purpose water projects and regulation of water quality with respect to interstate carriers. After passage of the SDWA, the federal government became involved in developing national drinking water regulations pursuant to the new law and in conducting research to support these regulations. States implement the federal mandates but also utilize their own statutory and regulatory requirements to protect drinking water quality. For example, the states play a significant role in oversight functions ranging from licensing of water treatment plant operators to the approval of new sources of supply and the approval of new treatment facility design. Local agencies such as health departments, environmental health programs, and building departments implement codes and ordinances that address water distribution systems, most often that portion of the infrastructure not controlled by public water systems. This section provides an overview of the various statutory and regulatory approaches that apply to distribution systems. Safe Drinking Water Act The SDWA (Public Law 93-523), enacted in 1974 and amended in 1986 (Public Law 99-339), 1988 (Public Law 100-572), and 1996 (Public Law 104-182), provides the statutory bases by which public water systems are regulated.
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Drinking Water Distribution Systems: Assessing and Reducing Risks Pursuant to the SDWA, the U.S. Environmental Protection Agency (EPA) is mandated to establish regulations for drinking water in the form of either maximum contaminant levels (MCL) or maximum contaminant level goals (MCLGs). MCLs are water quality standards that must be met by utilities and are enforced by state or federal agencies. Unlike MCLs, MCLGs are non-enforceable and are set at a level at which no known or anticipated adverse human health effects occur. Where it is not economically or technologically feasible to ascertain the level of a contaminant, a treatment technique is prescribed by EPA in lieu of establishing an MCL. For example, because the viable concentration of Giardia lamblia is difficult to measure, it has been established that if water is treated at a given pH, temperature, and chlorine concentration for a specified length of time (all of which are verified by the water utility), a fixed level of Giardia inactivation will take place. The SDWA also provides EPA with the authority to delegate the implementation of the SDWA requirements to the states through the process of primacy. Forty-nine (49) of the 50 states have accepted primacy, with Wyoming being the exception. The SDWA applies to public water systems, which can be publicly or privately owned. Public water systems are defined as providing drinking water to at least 25 people or 15 service connections for at least 60 days per year. As mentioned in Chapter 1, there are approximately 160,000 public water systems in the United States, providing water to more than 290 million people. Currently, 51 organic chemicals, 16 inorganic chemicals, seven disinfectants and disinfection byproducts (DBPs), four radionuclides, and coliform bacteria are monitored for compliance with the SDWA (EPA, 2005a). Standards for most contaminants are required to be met at the point of entry to the distribution system, such that the SDWA does not directly address distribution system contamination for most compounds. Despite these spatial restrictions, the SDWA does provide EPA with the authority to regulate contaminants within distribution systems—an authority that EPA has used to promulgate several regulations that address distribution system water quality including the Total Coliform Rule (TCR), the Lead and Copper Rule (LCR), the Surface Water Treatment Rule (SWTR), and the Disinfectants/Disinfection Byproducts Rule (D/DBPR). The 1996 amendments to the SDWA mandated that EPA conduct research to strengthen the scientific foundation for standards that limit public exposure to drinking water contaminants. Specific requirements were given for research on waterborne pathogens such as Cryptosporidium and Norovirus, DBPs, arsenic, and other harmful substances in drinking water. EPA was also directed to conduct studies to identify and characterize population groups, such as children, that may be at greater risk from exposure to contaminants in drinking water than is the general population. In response to that mandate EPA has developed a Multi-Year Plan that describes drinking water research program activities and plans for fiscal years 2003–2010 (see Box 2-1).
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Drinking Water Distribution Systems: Assessing and Reducing Risks BOX 2-1 EPA Multi-Year Plan for Drinking Water The Multi-Year Plan establishes three long-term goals: By 2010, develop scientifically sound data and approaches to assess and manage risks to human health posed by exposure to regulated waterborne pathogens and chemicals, including those addressed by the Arsenic, M/DBP, and Six-Year Review Rules. By 2010, develop new data, innovative tools, and improved technologies to support decision making by the EPA Office of Water on the Contaminant Candidate List and other regulatory issues, and to support implementation of rules by states, local authorities, and water utilities. By 2009, provide data, tools, and technologies to support management decisions by the EPA Office of Water, state, local authorities, and utilities to protect source water and the quality of water in the distribution system. Some of the tasks in the Multi-Year Plan related to distribution systems include: Collect data to assess the stability of arsenic in water distribution systems. Prepare a report on chlorine and chloramines to control biofilms in model distribution systems. Prepare a report on the mechanisms and kinetics of chloramine loss and DBP formation in distribution systems. This work includes the modeling of n-nitrosodimethylamine formation. Prepare a report on the effect of oxidizing conditions on metal releases, corrosion rate, and scale properties of distribution system materials. Prepare a report on biofilm formation rates in pilot-scale distribution systems. Report on the characterization and prediction of scale formation (including aluminum) in distribution systems. Prepare a report on the detection of opportunistic pathogens (E. coli, Aeromonas, Mycobacterium) in biofilms using molecular detection techniques. Collect data on the treatment conditions which may enhance the solubilization of arsenic-containing iron oxides within the distribution system. Prepare a report on the link between the distribution system and Mycobacterium avium complex (MAC) found in clinical cases. Prepare a report on characterization of drinking water distribution system biofilm microbial populations using molecular detection methods. Prepare a report on corrosion chemistry relationships and treatment approaches. Prepare a report on the impact of change from conventional treatment of surface water to alternative treatment (membrane) on biofilm growth in water distribution systems in support of regulation development. Improve methods for rapid detection of water quality changes. Conduct leaching studies to characterize organotin concentrations in distribution systems. SOURCE: EPA (2003a).
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Drinking Water Distribution Systems: Assessing and Reducing Risks Associated Federal Regulations There are several federal regulations that are designed to address specific distribution system water quality issues, although none of these regulations deal wholly with the integrity of distribution systems as defined in Chapter 1. The following provides a brief description of each of these regulations. National Interim Primary Drinking Water Regulations Following the passage of the SDWA, EPA adopted the National Interim Primary Drinking Water Regulations (NIPDWR) on December 24, 1975 and on July 9, 1976. The NIPDWR established the first national standards for drinking water quality. These standards included limits for ten inorganic chemicals, six organic pesticides, turbidity, and five radionuclides. In addition, the NIPDWR established standards for microbiological contamination based on total coliform organisms. Total Coliform Rule The primary purpose of the TCR is to ensure public health protection from microbial contamination of drinking water, and it applies to all public water systems. It is the only regulation that is intended to measure the microbiological quality of water within that part of the distribution system controlled by the public water supply. In 1989 EPA promulgated the TCR as a revision to the existing regulation that required public water systems to monitor for coliform organisms in the distribution system. The TCR changed the concept of monitoring for coliform organisms from one based on measuring the concentration of coliforms to determining the presence or absence of coliforms. In addition, the TCR established an MCL based on the presence or absence of total coliforms, modified monitoring requirements including testing for fecal coliforms or E. coli, required the use of a sample siting plan, and also required sanitary surveys for water systems collecting fewer than five samples per month. The MCL for total coliforms is as follows: For a system serving more than 33,000 people and collecting more than 40 samples per month, a non-acute violation occurs when more than 5.0 percent of the samples collected during the month are total coliform positive. For systems serving 33,000 people or less and collecting less than 40 samples per month, a non-acute violation occurs when more than one sample is total coliform positive in a given month.
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Drinking Water Distribution Systems: Assessing and Reducing Risks Any fecal coliform positive repeat sample, E. coli positive repeat sample, or any total coliform positive repeat sample following a fecal coliform or E. coli positive routine sample constitutes an acute violation of the MCL for total coliforms. The sampling frequency ranges from one sample per month for water systems serving 25 people to 480 samples per month for the largest of water systems serving greater than 3,960,000 people (40 CFR 141.21 & 141.63). Sampling locations, identified in the sample siting plan, are required to be representative of water throughout the distribution system, including all pressure zones and areas supplied by each water source and distribution reservoir. Trihalomethane Rule In 1979 EPA promulgated a rule that established a drinking water standard for trihalomethanes (THMs), a group of chemicals produced as a consequence of chlorine disinfection. These chemicals are regulated because of the concern over their potential carcinogenic risk. The drinking water standard set at 0.10 mg/L addressed the total concentration of four specific THMs: chloroform, dichlorobromomethane, dibromochloromethane, and bromoform. This rule was the first to regulate the chemical quality of drinking water in the distribution system. The rule affected public water systems serving greater than 10,000 people because EPA was concerned that smaller systems would not have sufficient expertise available to deal with elevated levels of THMs without compromising microbiological safety. Water systems were required to sample quarterly at a minimum of four points in the distribution system and determine the average concentration of the four sample points. Compliance with the standard was based on the running average of any four consecutive quarterly results (EPA, 1979). Surface Water Treatment Rule On June 29, 1989, the EPA published the SWTR in response to Congress’ mandate to require systems that draw their water from surface water sources (rivers, lakes, and reservoirs) and groundwater under the influence of surface water to filter, where appropriate, and to disinfect their water before distribution. The SWTR seeks to reduce the occurrence of unsafe levels of disease-causing microbes, including viruses, Legionella bacteria, and the protozoan Giardia lamblia. The SWTR requires water systems that filter to meet specific turbidity limits, and it assumes that this will achieve reductions in Giardia lamblia cysts (99.9 per cent) and viruses (99.99 per cent). Also, water systems are required to continuously monitor the residual disinfection concentration entering the distribution system, except those serving less than 3,300 people, which are allowed to
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Drinking Water Distribution Systems: Assessing and Reducing Risks collect grab samples. Furthermore, water systems (both filtered and unfiltered) are required to ensure a residual disinfectant concentration of not less than 0.2 mg/L entering the distribution system and to maintain a detectable residual disinfectant concentration in the distribution system measured as total chlorine, combined chlorine, or chlorine dioxide. The use of the heterotrophic bacteria plate count (HPC) is allowed as a surrogate for a detectable disinfectant in the distribution system provided that the concentration of heterotrophic bacteria is less than or equal to 500 colony forming units/milliliter (EPA, 1989). Samples for measuring residual disinfectant concentrations or heterotrophic bacteria must be taken at the same locations in the distribution system and at the same time as samples collected for total coliforms. Lead and Copper Rule The LCR was published in June 1991 and is intended to address the concern over chronic exposure of young children to lead in drinking water, the lead being principally from the leaching of the chemical from premise plumbing, fixtures, solder, and flux, and acute effects from copper. Indeed, since June 19, 1986, the use of solder and flux with more than 0.2 percent lead and the use of pipes and pipe fittings with more than 8.0 percent lead in the installation or repair of any public water system or plumbing in residential or non-residential facilities has been prohibited. States are required to enforce these requirements through state or local codes. Unlike the TCR, which is intended to assess water quality that is representative of the entire distribution system in a dynamic or flowing state, the LCR is predicated on assessing water quality that represents worst case conditions. The LCR established monitoring requirements for tap water at “primary” locations—homes that contain lead pipes or copper pipes with lead solder installed after 1982. These homes were generally identified through a review of permits and records in the files of the building department(s) that indicate the plumbing materials installed within publicly and privately owned structures connected to the distribution system and the material composition of the service connections. The number of required samples depends on the size of the water system. Samples are collected from interior taps where water is typically drawn for consumption and after the tap has been left unused in a static state for a minimum of six hours. Table 2-1 describes the standard and reduced monitoring requirements of the LCR. The LCR also established requirements for corrosion control treatment, source water treatment, lead service line replacement, and public education. The LCR establishes “action levels” in lieu of MCLs. The action level for lead was established at 0.015 mg/L while the action level for copper was set at 1.3 mg/L. An action level is exceeded when greater than 10 percent of samples collected from the sample pool contain lead levels above 0.015 mg/L or copper levels above 1.3 mg/L. Water systems exceeding the respective action level are
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Drinking Water Distribution Systems: Assessing and Reducing Risks TABLE 2-1 Standard and Reduced Monitoring Requirements of the Lead and Copper Rule System size (number of people served) Standard monitoring requirements (number of sites) Reduced monitoring requirements* (number of sites) 100,000 100 50 10,001 to 100,000 60 30 3,301 to 10,000 40 20 501 to 3,300 20 10 101 to 500 10 5 < 100 5 5 *Utilities can reduce the number of sampling sites and the frequency of monitoring from the required semi-annual frequency to a lesser frequency if their water system meets the following conditions: Reduce to Annual monitoring if: the system serves less than 50,000 people and the lead and copper levels are less than the action level for two consecutive six-month monitoring periods or, the system meets Optimal Water Quality Parameter (OWQP) specifications for two consecutive six-month monitoring periods Reduce to Triennial Monitoring if: the system serves more than 50,000 people and the lead and copper levels are less than the action level for three consecutive years or, the system meets OWQP specifications for three consecutive years of monitoring or, the system has 90th percentile lead levels less than 0.005 mg/L and 90th percentile copper levels less than 0.65 mg/L for two consecutive six-month monitoring periods or, The system has demonstrated optimized corrosion control Reduce to Monitoring once every nine years if: the system serves less than 3,300 people, the distribution system, the service lines, and the premise plumbing are free of lead-containing and copper-containing materials and, the system has 90th percentile lead levels less than 0.005 mg/L and 90th percentile copper levels less than 0.65 mg/L for one six-month monitoring period. required to install corrosion control treatment and conduct lead service line replacement and mandatory lead education. Information Collection Rule In May 1996, EPA promulgated the Information Collection Rule (ICR), which established monitoring and data reporting requirements for large public water systems including surface water systems serving at least 100,000 people and groundwater systems serving at least 50,000. The rule was intended to provide EPA with information on the occurrence in drinking water of (1) DBPs and (2) disease-causing microbes including Cryptosporidium (EPA, 1996). EPA used the information generated by the rule to develop new regulations for disinfectants and DBPs (EPA, 2006a).
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Drinking Water Distribution Systems: Assessing and Reducing Risks Operator Certification Pursuant to the SDWA amendments of 1996, EPA in cooperation with the states was directed to issue guidelines specifying minimum standards for certification and recertification of the water treatment and distribution system operators of all public water systems. The guidelines were required to take into account the size and complexity of the system, existing state programs, and other factors aimed at providing an effective program at reasonable cost to states and public water systems (EPA, 1999). EPA, through grants to the states allocated on the basis of “reasonable costs,” was required to reimburse training and certification costs for operators of systems serving 3,300 persons or fewer, including an appropriate per diem for unsalaried operators who had to undergo training as a result of the federal requirement. States are required to adopt and implement a program for the certification of operators of public water systems that meet or are equivalent to the requirements of the EPA guidelines. Stage 1 Disinfection and Disinfection Byproducts Rule On December 16, 1998, EPA published the Stage 1 D/DBPR, making more stringent the existing standard for trihalomethanes as well as establishing new standards for disinfectants and other DBPs (EPA, 1998a). The rule, which applies to all public water systems, lowers the existing TTHM standard from 0.10 mg/L to 0.080 mg/L and establishes new standards for five haloacetic acids (HAAs) at 0.060 mg/L, bromate at 0.010 mg/L, and chlorite at 1.0 mg/L. In addition, the Rule establishes limits for disinfectants including chlorine, chloramine, and chlorine dioxide within the distribution system (via Maximum Residual Disinfectant Levels or MRDLs). For chlorine and chloramines, samples for measuring residual disinfectant must be taken at the same locations in the distribution system and at the same time as samples collected for total coliforms. For chlorine dioxide, samples must be taken daily at the entrance to the distribution system. Compliance with the MRDLs for chlorine and chloramines is based on the annual running average of all monthly samples collected, while compliance with the MRDL for chlorine dioxide is based on each daily sample. Finally, the Rule requires enhanced coagulation for certain systems in order to achieve specific reductions of DBP precursor material (as measured by total organic carbon concentrations). Interim Enhanced Surface Water Treatment Rule In December 1998, EPA promulgated the Interim Enhanced Surface Water Treatment Rule (IESWTR) that applied to public water systems serving greater than 10,000 people that were subject to the original SWTR. The IESWTR established a requirement for the reduction of Cryptosporidium and a more strin-
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Drinking Water Distribution Systems: Assessing and Reducing Risks gent turbidity requirement for filtered water supplies, among other provisions. The IESWTR also requires certain water systems to evaluate their disinfection practices to ensure that there will be no significant reduction in microbial protection as the result of modifying disinfection practices to meet MCLs specified by the Stage 1 D/DBPR. In addition, the IESWTR requires that all finished water storage facilities, for which construction began after February 16, 1999, be covered. EPA further indicated that it would consider whether or not to require the covering of existing reservoirs during the development of subsequent microbial regulations (EPA, 1998b). Long Term 1 Enhanced Surface Water Treatment Rule In 2002 EPA promulgated the Long Term 1 Enhanced Surface Water Treatment Rule (LT1ESWTR). The LT1ESWTR applies to public water systems that use surface water or groundwater under the direct influence of surface water and serve fewer than 10,000 persons. The purposes of the LT1ESWTR are to improve control of microbial pathogens, specifically Cryptosporidium, in drinking water and to address risk trade-offs with DBPs. The LT1ESWTR requires systems to meet strengthened filtration requirements as well as to calculate benchmark levels of microbial inactivation to ensure that microbial protection is not jeopardized if systems make changes to comply with requirements of the Stage 1 D/DBPR (EPA, 2002a). The only difference between this rule and the IESWTR is the size of the affected community. Stage 2 Disinfectants and Disinfection Byproducts Rule On January 4, 2006, EPA adopted the Stage 2 D/DBPR that makes more stringent the previous rule regulating certain DBPs. Under the Stage 1 D/DBPR water systems are allowed to average the DBP sample results from across the distribution system. As a result some customers could be exposed to levels of DBPs that consistently exceeded the MCLs and that might escape detection. The new rule requires that water systems meet the MCLs for THMs and HAAs at each sampling location based on the running annual average of any four consecutive quarterly sample results at that location. The intent of this change is to reduce DBP exposure and provide more equitable health protection and to lower potential cancer, reproductive, and developmental risks (EPA, 2006a). To determine the locations within the distribution system where the highest levels of THMs and HAAs are expected to occur, the Rule requires water systems to conduct an Initial Distribution System Evaluation. Initial Distribution System Evaluations are studies that evaluate THM and HAA levels at various points within the distribution system. The results from these studies along with existing compliance monitoring information will be used to determine future compliance monitoring locations.
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Drinking Water Distribution Systems: Assessing and Reducing Risks Long Term 2 Enhanced Surface Water Treatment Rule On January 5, 2006, EPA adopted the Long Term 2 Enhanced Surface Water Treatment Rule (LT2ESWTR). The LT2ESWTR applies to public water systems that use surface water or groundwater under the direct influence of surface water. The purpose of the LT2ESWTR is to reduce disease incidence associated with Cryptosporidium and other pathogenic microorganisms in drinking water. The LT2ESWTR supplements existing regulations by targeting additional Cryptosporidium treatment requirements to higher risk systems based on actual monitoring data of source water quality. The LT2ESWTR also contains provisions to mitigate risks from uncovered finished water storage facilities. Water systems with uncovered finished water storage reservoirs are required to cover the reservoir or treat the reservoir discharge to the distribution system to achieve inactivation and/or removal of at least 2-log Cryptosporidium, 3-log Giardia, and 4-log virus (EPA, 2006b). Finally, to ensure that systems maintain microbial protection as they take steps to reduce the formation of DBPs the LT2ESWTR requires water systems that proposed to modify their disinfection process to reduce THMs and HAAs to assess the existing levels of disinfection that the system provides. Systems are required to establish a benchmark, which is the system’s lowest monthly average microbial inactivation. If the benchmark is more than the required inactivation of 3-log removal for Giardia and 4-log removal for viruses, the system may consider decreasing the amount of disinfectant added or the contact time, or altering other disinfection practices to lower THM and HAA levels (EPA, 2006b). Unregulated Contaminant Monitoring Rule 2 On August 22, 2005, EPA proposed the second of two Unregulated Contaminant Monitoring Rules (UCMR2), which will require monitoring for a list of 26 chemical contaminants suspected to be present in drinking water. The purpose of the UCMR2 is to develop data on the occurrence of these contaminants in drinking water, the size of the population exposed to these contaminants, and the levels of the exposure. This information will be used along with health effects information to determine whether or not drinking water standards should be established for these contaminants. All community water systems and non-transient, non-community water systems serving more than 10,000 people will be required to monitor, while a representative sample of 800 community water systems and non-transient, non-community water systems serving less than 10,000 people will have to carry out monitoring. The monitoring is proposed to begin in 2007. Unlike the first UCMR (which is not discussed above), the UCMR2 will include contaminants that are considered potential DBPs and for which monitoring will be conducted in the distribution system. These contaminants include the nitrosamines N-nitroso-diethylamine (NDEA), N-nitroso-dimethylamine
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Drinking Water Distribution Systems: Assessing and Reducing Risks (NDMA), N-nitroso-di-n-butylamine (NDBA), N-nitroso-di-n-propylamine (NDPA), N-nitroso-methylethylamine (NMEA) and N-nitroso-pyrrolidine (NPYR). Nitrosamines are considered potential human carcinogens, and NDMA has been shown to form in chlorinated or chloraminated water as a result of disinfection (EPA, 2005b). Water Security-related Directives and Laws Although not a new issue, security has become paramount to the water utility industry since the events of September 11, 2001. The potential for natural, accidental, and purposeful contamination of water supply has been present for decades whether in the form of earthquakes, floods, spills of toxic chemicals, or acts of vandalism. For example, in May 1998, President Clinton issued Presidential Directive (PDD) 63 that outlined a policy on critical infrastructure protection, including our nation’s water supplies. However, it was not until after September 11, 2001, that the water industry truly focused on the vulnerability of the nation’s water supplies to security threats. In recognition of these issues, President Bush signed Public Health Security and Bioterrorism Preparedness and Response Act of 2002 (the “Bioterrorism Act”) into law in June 2002 (PL107-188). Under the requirements of the Bioterrorism Act, drinking water utilities are required to prepare vulnerability assessments and emergency response plans for water systems serving at least 3,300 people. *** Table 2-2 summarizes the key requirement(s) of federal rules and regulations from a distribution system perspective. State Regulatory Programs State regulatory programs that address water distribution systems can vary significantly. In general most states have statutory and regulatory requirements that cover (1) design, construction, operation, and maintenance of distribution systems, (2) cross-connection control, and (3) plumbing products certified for use pursuant to American National Standards Institute/ NSF International (ANSI/NSF) standards 60 and 61. Furthermore, most states have adopted a plumbing code that dictates the types of materials that can be used for premise plumbing, although these codes are not generally enforced from a state statutory or regulatory standpoint but rather are implemented at the local county and/or municipal level.
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Drinking Water Distribution Systems: Assessing and Reducing Risks Establish corrective action procedures Verify and validate the HACCP Plan Establish record keeping and responsibility HACCP is a risk management program because utilities use it to first identify and evaluate hazards/risks, and then to establish control systems to minimize the occurrence and effects of incidents that may impact the safety and quality of the water. A water utility can choose to apply HACCP to any one “process”—i.e., watershedprotection, treatment, or the distribution system. Some utilities may already have good watershed protection programs and good control over treatment facilities, and so may view the distribution system as a priority. However, because HACCP is a proactive approach to system management that helps the utility to identify “hazards” further upstream, it works quite well as a comprehensive system plan, from source to tap. For maximum benefits, it is important to leave the decision to individual utilities and not be too prescriptive about how to apply HACCP (Friedman et al., 2005). A recently completed project sponsored by the AWWA Research Foundation (Friedman et al., 2005) describes HACCP pilot studies conducted with three utilities’ distribution systems—Greater Cincinnati Water Works, Cincinnati, Ohio; Calgary Water Works, Calgary, Alberta; and the City of Everett, Everett, Washington. Training workshops were held at each utility location to explain HACCP terminology and to initiate development of the utility’s HACCP plan. Each participating utility formed a HACCP team to further develop the HACCP plan and to guide its implementation. The goal was for each utility to implement their HACCP plan over a 12-month period during which certain operational and water quality parameters would be monitored. The participating utilities found that the implementation of HACCP to water supply distribution was feasible and practical, but that the time and resource requirements were greater than originally anticipated. The development of the HACCP plan was useful in honing in on the most important risks and process controls for water quality management. Within the 12-month pilot study period, none of the three participating utilities developed a fully implemented HACCP program for certification. A longer period of time and/or a greater resource commitment was likely to be required before the HACCP systems would be considered fully implemented, complete, and certifiable. Box 2-2 describes two other HACCP case studies in detail, for Austin, Texas, and Burwick, Maine. NSF International provides HACCP certification to water utilities in the United States through its HACCP-9000 registration program. The program consists of third-party verification of utility HACCP plans, combined with a registration with ISO 9000 standards. However, adoption of the HACCP approach need not be tied formally to such administrative programs. HACCP could be an integral part of a utility’s distribution system management plan, either in addition to or in lieu of G200 (given the substantial similarities between the two programs). In particular, HACCP is useful for improving a utility’s awareness of its existing databases and how it can better manage the information
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Drinking Water Distribution Systems: Assessing and Reducing Risks contained within, and for promoting record keeping and reporting. Critics contend that HACCP is little more than properly operating a distribution system. Indeed, there may be little value added in the United States where utilities are relatively heavily regulated compared to other countries where HACCP has been successfully adopted (such as Australia, which has no national water quality standards). However, advocates contend that the part of HACCP that most utilities do not already engage in is checking to verify that actions are working (Martel, 2005). Furthermore, HACCP puts an increased focus on operator training, which can be ignored in the face of so many other competing activities, like compliance monitoring. The program is more likely to be adopted by larger-size utilities because of the need for a larger staff and budget to carry out HACCP. Nonetheless, there is another practical consideration that makes G200 a more attractive organizing program for distribution systems than HACCP. Programs like HACCP are ideally suited to industries that experience little variation on a day-to-day basis (such as food and beverage processing plants) and are not as easily adapted to the dynamic nature of drinking water distribution systems that may experience changes in water quality depending on season, source of supply, and changing daily demands. Furthermore, unplanned disruptions such as water main breaks require immediate responses in areas that may not be considered critical control points, making it very difficult to proactively control contamination events. Finally, the vast number of locations within a distribution system that could be potential critical control points (presumably every residence where a cross connection exists) argues against the formal adoption of HACCP. The cost of creating a HACCP plan for a community of 10,000 may be in the range of $10,000, including a day- or two-day-long workshop. Water Safety Plans In 1994, the World Health Organization (WHO) adapted the HACCP program through Water Safety Plans, which can be prepared for individual water systems. The WHO’s Guidelines for Drinking Water Quality (2004) describe an approach to follow in preparing Water Safety Plans. The approach is to identify, prioritize, and prevent risks arising from hazards associated with distribution of drinking water. The three critical components of a water safety plan are: System assessment regarding both the quantity and quality of supplied water Identification of control measures Management plans describing actions during both normal and extreme conditions and documenting, monitoring, communication, and improvement efforts.
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Drinking Water Distribution Systems: Assessing and Reducing Risks BOX 2-2 HACCP Case Studies There are few case studies of where HACCP has been applied to distribution system management. One involves a relatively small utility, the South Berwick Water District, in South Berwick, Maine, which serves about 4,000 people. At this utility, a HACCP training workshop was held on June 2003 to assemble the HACCP team, which included the superintendent, foreman, and a service person, as well as outside experts such as an engineer familiar with the South Berwick system, a microbiologist from EPA, a state regulator who was an expert on cross-connection control, and a risk manager from the bottled water industry. As in other cases where HACCP has been applied, assembling a team that has as many people from different cross sections of the water utility as possible is one of the benefits of doing HACCP, but because of the small size of the utility this required outside assistance. The process flow diagram for the entire water system is shown in Figure 2-1. FIGURE 2-1 Process Flow Diagram for the South Berwick Water District. SOURCE: Reprinted, with permission, by Martel (2005).© 2006 by AwwaRF. Three priority hazards were identified by the HACCP team, two of which involve the distribution system: (1) backflow through unprotected cross connections, (2) long dead-end mains with zero or poor disinfectant residual, and (3) unintentional contamination of shallow well points at the Agamenticus Wellfield. It should be noted that it was very difficult to gather enough information to determine the frequency of occurrence or the severity of these hazards, given the utility’s lack of data. For this reason, South Berwick’s initial HACCP plan focused on monitoring activities to further characterize these hazards and improve existing control measures. Unfortunately, the HACCP plan was not fully implemented because of a lack of manpower and because of other priorities. With only three full-time employees at the utility, daily system operation and maintenance took priority over HACCP plan implementation. Furthermore, the utility personnel were involved with building a new treatment facility, developing a new rate structure, and addressing local and state political issues. This case study illustrates the need for sufficient manpower to successfully implement a HACCP Plan. A second case study is from Austin, Texas, a much larger water supply that serves approximately 770,000 people. The interdisciplinary HACCP team consisted primarily of inhouse staff: the water quality manager, the water laboratory supervisor, an engineer
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Drinking Water Distribution Systems: Assessing and Reducing Risks /planner, a construction inspector, the cross-connection control supervisor, the Assistant Director of Treatment, the Infrastructure Superintendent, and a state regulator. A HACCP pilot study was conducted from May 2003 to September 2004. The team focused on one pressure zone within the distribution system for the HACCP pilot study (see the flow process diagram below in Figure 2-2): FIGURE 2-2 Flow Process Diagram for the Austin Water Supply. SOURCE: Reprinted, with permission, from Martel (2005).© 2006 by AwwaRF. Austin’s HACCP team identified two high priority hazards: backflow through unprotected cross connections (focusing specifically on irrigation and hydrant vandalism) and contamination from new construction sites (primarily via improper valve turning). Austin found that HACCP is more complex than initially envisioned. Originally, the utility thought that HACCP would involve identifying critical flow paths within the distribution system and monitoring these flow paths more intensively to assure water quality to downstream sites. Instead, by nature of the selected hazards, the measures used to control these hazards focused on operations and maintenance activities rather than water quality monitoring. This approach added layers of complexity to the existing monitoring program. On a positive note, the HACCP approach helped the utility (1) improve understanding of their distribution system hazards; (2) heighten employee awareness of pressure zone boundaries, pressure transients, the need to maintain pressure and to respond quickly to main breaks in small pressure zones; (3) improve awareness of existing databases and monitoring programs; (4) improve data management skills; (5) identify needed improvements to existing databases; and (6) improve reporting procedures for acceptance of new mains. SOURCE: Martel et al. (2006).
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Drinking Water Distribution Systems: Assessing and Reducing Risks Water safety plans present an affordable risk management tool for all drinking water suppliers, regardless of size. While some critical elements of the plan should be assured by all systems, more costly or time-consuming elements, characterized as not critical, may be added to the plans based on budgetary and staff availability. The most critical elements of the water safety plan documents include system description, water flow diagrams, hazard identification, identification of a team, and contingency plan. Additional items include specification of chemicals and materials, job descriptions for staff responsible for individual operations, corrective actions for deviations, record-keeping procedures, validation data, and incident documentation procedures. Finally, optional elements may include manuals for hygiene, preventive maintenance, and equipment calibration; job descriptions for all staff; training programs and records; documentation of corrective actions, audits, and verification procedures; and consumer complaint policy and procedures. Clearly, the elements of a Water Safety Plan closely resemble the elements of a HACCP Plan: (1) source-to-tap system assessment; (2) control measures for identified hazards and operational monitoring of control measures; and (3) a management plan that documents the system assessment, control measures, monitoring plan, corrective action procedures to address water quality incidents, communication plan, and supporting programs such as standard operating procedures, employee training, and risk communication. Both HACCP and Water Safety Plans should be used continuously. A 2004 conference sponsored by NSF International examined a variety of risk management approaches, including HACCP, ISO certification, Water Safety Plans, and Environmental Management Systems. Not only were many commonalities among these programs evident, the distinctions between them were unclear. The conference presented a number of domestic and international case studies where water utilities had utilized one of these risk management systems, but no case studies targeting the distribution system were discussed. Indeed, the choice of the “right” program for any given water utility may present a challenge, specifically because there is no precedence for using these programs for distribution system management, but also because of a lack of coordination between the programs, a lack of tangible benefits beyond what a utility already accomplishes, and inefficient communication to the public about the programs. It is up to an ambitious utility manager and staff to learn about the programs, evaluate their applicability, and select one. Training for Operators, Inspectors, and Related Personnel While utilities endeavor to optimize their infrastructure and operate the distribution system to minimize degradation, an integral component not to be ignored are the operators, inspectors, and related personnel charged with running and monitoring the system. Inevitably, the operators and field personnel serve as guardians to minimize degradation in the distribution system and ensure wa-
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Drinking Water Distribution Systems: Assessing and Reducing Risks ter quality is maintained for the consumer. Training of distribution system operators was identified as a high priority issue for reducing risk in drinking water distribution systems (NRC, 2005). The need for the continuing and intensive training of operators of distribution systems has increased recently for three reasons. First, as federal and state regulations become increasingly stringent and more complex, they require enhanced skills for proper sample collection and preservation, as well as better understanding of aquatic chemistry and biology for proper implementation and interpretation of results. Second, in many systems the D/DBPR (EPA, 1998a) created a shift in the use of disinfectants in the distribution systems from a relatively simple application of chlorine to the rather complicated application and maintenance of chloramine. Finally, with an increase in the importance of security of drinking water pipes, pumps, reservoirs, and hydrants, there is a corresponding increase in the responsibility of operators to make decisions during perceived security events. Typically distribution system operators, mechanics, and field crews are well trained in the mechanical aspects of water delivery (such as pipe replacement and repair; pump, valve, and storage facility operation; etc.) and safety. In cases where contractors are used to repair or maintain the infrastructure (for example, many utilities allow certified plumbers to perform the tasks related to backflow prevention and cross-connection control), diligence of construction inspectors in providing oversight is of paramount importance because the contractor may or may not be following standard practices. A case in point regarding the importance of training plumbers is the ban on lead solder implemented in the late 1980s. Because the responsibility for high lead levels in drinking water falls on the utility, many utilities were actively engaged in training plumbers about the dangers of lead from the use of lead solder and about the new requirements of the LCR. This training was critical to reducing the risk of lead exposure from drinking water. The importance of operator training in protecting public health from contaminated drinking water cannot be overstated. A recent critique of the Walkerton, Ontario Inquiry Report (Hrudey and Walker, 2005) claims that lives could have been saved had operators been properly trained. Failure to perform basic monitoring duties and understand the vulnerability of the system to a contamination event in May 2000 led to more than 2,300 cases of waterborne disease in a system of only 5,000 people. “Water system operators must be able to recognize that the threats to their system contrasted with the system’s capability to cope. They have a professional responsibility to ensure deficiencies are identified, made known to management, and effectively remedied. Pending necessary improvements, operators must increase their vigilance and develop contingency plans to cope with periods of stress. Contingency plans should be practiced using simulated incidents before a real crisis develops” states Hrudey. Justice O’Connor who led the multi-million dollar inquiry into the Walkerton tragedy concluded that “Ultimately, the safety of drinking water is protected by effective
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Drinking Water Distribution Systems: Assessing and Reducing Risks management systems and operating practices, run by skilled and well-trained staff” (Hrudey and Walker, 2005). Operator training classes and seminars are offered through industry associations (e.g., AWWA, the National Rural Water Association) and third party contractors. The International Association for Continuing Education and Training (IACET) has recently developed certification for trainers, which is a positive step toward ensuring the quality of instructors who are providing operator training. However, it is well recognized that nationally there is a paucity of adequate training facilities, instructors, and apprentice programs to replace an experienced workforce who will be retiring in the coming decade (Brun, 2006; Eaton, 2006; McCain and Fahrenbruch, 2006; Pomerance and Means, 2006). As discussed earlier, there are existing EPA guidelines for the certification of treatment plant operators and distribution system operators (EPA, 1999), which have subsequently been implemented by states (leading to state requirements for certification). However, these requirements are not always enforced, particularly on small systems. Stronger enforcement of the distribution system operator certification requirements developed by individual states could be a mechanism to support training and apprentice programs. Also, future regulations need to include mechanisms to fund training and apprentice programs specifically for distribution system operators. Finally, while existing certification exams test generic knowledge, future requirements should ensure that operators understand the system in which they work and are familiar with portions of operating plans that apply to performance of their daily activities. CONCLUSIONS AND RECOMMENDATIONS The Total Coliform Rule, the Surface Water Treatment Rule, the Disinfectants/ Disinfection By-Products Rule, and the Lead and Copper Rule are the federal regulations that address water quality within the distribution system, and they do so in a piecemeal fashion. These rules were not intended to address distribution system integrity as defined in Chapter 1, which consists of physical, hydraulic, and water quality integrity. For example, the TCR considers only that microbial contamination indicated by fecal parameters. Nor does the SDWA contemplate federal actions that would address premise plumbing, with the exception of lead in plumbing materials. As a result a more comprehensive approach needs to be taken to ensure that the overall integrity of distribution systems is maintained. The following regulatory recommendations are made. EPA should work closely with representatives from states, water systems, and local jurisdictions to establish the elements that constitute an acceptable cross-connection control program. Although states, either through drinking water regulations or state plumbing codes, have cross-connection control requirements in place, these requirements are inconsistent amongst states. State oversight of cross-connection control programs varies and is subject to
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Drinking Water Distribution Systems: Assessing and Reducing Risks availability of resources. If states expect to maintain primacy over their drinking water programs, they should adopt a cross-connection control program that includes a process for hazard assessment, the selection of appropriate backflow devices, certification and training of backflow device installers, and certification and training of backflow device inspectors. Although tracking compliance by water systems is also an important element, the resource implications of tracking and reporting requirements should be carefully considered. EPA may need to allow use of federal funds for training of backflow prevention device inspectors for small water systems. Existing plumbing codes should be consolidated into one uniform national code. Although similar with regard to cross-connection control requirements and other premise plumbing protection measures, the two principal plumbing codes that are used nationally, the UPC and the IPC, have different contents and permit different materials and devices. These differences appear to be addressable, recognizing that the two code developing organizations may have other issues that would need to be resolved. In addition to integrating the codes, efforts should be made to ensure more uniform implementation of the plumbing codes. Their implementation can vary significantly between jurisdictions, which can have major impacts on the degree of public health protection afforded to their constituents. For utilities that desire to operate beyond regulatory requirements, adoption of G200 or an equivalent program is recommended to help utilities develop distribution system management plans. G200 has advantages over other voluntary programs, such as HACCP, in that it is more easily adapted to the dynamic nature of drinking water distribution systems. More attention should be paid to having adequate facilities, instructors, and apprentice programs to train utility operators, inspectors, foremen, and managers. The need for the continuing and intensive training of operators of distribution systems has increased as a result of more sophisticated federal and state regulations, the shift in the use of disinfectants in the distribution system, and the increase in importance of security of drinking water distribution systems. Recent development of IACET certification for trainers is a positive step toward the quality of instructors providing operator training. Future regulations need to include mechanisms to fund training and apprentice programs. REFERENCES American Backflow Prevention Association (ABPA). 1999. American Backflow Prevention Association State Program Survey. Available on-line at: http://www.abpa.org/originalsite/ABPA_Survey_Report.pdf. Accessed May 4, 2006. AWWA/ANSI. 2004. G-200 Distribution Systems Operation and Management. Denver, CO: AWWA.
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Drinking Water Distribution Systems: Assessing and Reducing Risks Association of State Drinking Water Administrators (ASDWA). 1999. Survey of State Cross-Connection Control Programs. September 29, 1999. Washington, DC: ASDWA. ASDWA. 2003. Summary of Results from the ASDWA Distribution System & TCR Survey, Design and Construct & Operation and Maintenance. Washington, DC: ASDWA. ASDWA. 2004. Survey of State Adoption of ANSI/NSF Standards 60 and 61. Washington, DC: ASDWA. Blackburn, B. G., G. F. Craun, J. S. Yoder, V. Hill, R. L. Calderon, N. Chen, S. H. Lee, D. A. Levy, and M. J. Beach. 2004. Surveillance for waterborne-disease outbreaks associated with drinking water—United States, 2001–2002. MMWR 53(SS-8):23– 45. Brun, P. 2006. Is it workforce planning or succession planning? Source 20:6. Chaney, R. 2005. The Uniform Plumbing Code: development, maintenance and administration as a pathway to reducing risk. April 18, 2005. Presented to the NRC Committee on Public Water Supply Distribution Systems. Washington, DC. Codex Alimentarius Commission. 1993. Guidelines for the Application of the Hazard Analysis Critical Control Point (HACCP) System, CAC/GL 18-1993. Rome, Italy: Codex Alimentarius Commission and the FAO/WHO Food Standards Program, Food and Agriculture Organization of the United Nations and World Health Organization. Codex Alimentarius Commission. 1997. Guidelines for the Application of the HACCP System. Rome, Italy: Codex Alimentarius Commission and the FAO/WHO Food Standards Program, Food and Agriculture Organization of the United Nations and World Health Organization. Craun, G. F., and R. L. Calderon. 2001. Waterborne disease outbreaks caused by distribution system deficiencies. J. Amer. Water Works Assoc. 93(9):64–75. Eaton, G. 2006. San Diego County Water Authority prepares for the future. Source 20:14–15. Environmental Protection Agency (EPA). 1979. National Interim Primary Drinking Water Regulations for the Control of Trihalomethanes in Drinking Water, Final Rule. Federal Register 44:68641. EPA. 1989. National Primary Drinking Water Regulations: Filtration, Disinfection, Turbidity, Giardia lamblia, Viruses, Legionella, and Heterotrophic Bacteria; Final Rule (SWTR). Federal Register 54:27486. EPA. 1991. National Primary Drinking Water Regulation: Lead and Copper Rule, Final Rule. Federal Register 56:26460. EPA. 1996. National Primary Drinking Water Regulations: Monitoring Requirements for Public Drinking Water Supplies; Final Rule. Federal Register 61:24353. EPA. 1998a. National Primary Drinking Water Regulations: Disinfectants and Disinfection Byproducts, Final Rule. Federal Register 63:69389. EPA. 1998b. National Primary Drinking Water Regulations; Interim Enhanced Surface Water Treatment Rule; Final Rule. Federal Register 63:69477. EPA. 1999. Final guidelines for the certification and recertification of the operators of community and nontransient noncommunity public water systems. Federal Register 64:5915–5921. EPA. 2002a. National Primary Drinking Water Regulations; Long Term 1 Enhanced Surface Water Treatment Rule, Final Rule. Federal Register 67:1811.
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Drinking Water Distribution Systems: Assessing and Reducing Risks EPA. 2002b. Potential contamination due to cross-connections and backflow and the associated health risks, an issue paper. Washington, DC: EPA Office of Ground Water and Drinking Water. EPA. 2003a. Drinking Water Research Program, Multi-Year Plan, 2003. Washington, DC: EPA Office of Research and Development. Available on-line at: http://www.epa.gov/osp/myp/dw.pdf. Accessed May 4, 2006. EPA. 2003b. Cross-Connection Control Manual. Washington, DC: EPA. EPA. 2005a. FACTOIDS: Drinking Water and Ground Water Statistics for 2004. Washington, DC: EPA. EPA. 2005b. Unregulated Contaminant Monitoring Regulation (UCMR) for Public Water Systems Revisions. Federal Register 70:49093. EPA. 2006a. National Primary Drinking Water Regulations: Stage 2 Disinfectants and Disinfection Byproducts Rule; National Primary and Secondary Drinking Water Regulations, Final Rule. Federal Register 71:387. EPA. 2006b. National Primary Drinking Water Regulations: Long Term 2 Enhanced Surface Water Treatment Rule, Final Rule. Federal Register 71:653. Friedman, M., G. Kirmeyer, G. Pierson, S. Harrison, K. Martel, A. Sandvig, and A. Hanson. 2005. Development of distribution system water quality optimization plans. Denver, CO: AwwaRF. Hrudey, S. E., and R. Walker. 2005. Walkerton—5 years later tragedy could have been prevented. OpFlow 31:1–7. International Association of Plumbing and Mechanical Officials (IAPMO). 2003. Uniform Plumbing Code, 2003 edition. Ontario, CA: IAPMO. IAPMO. 2005. Can we make it work? Available on-line at http://www.iapmo.org/iapmo/news/code-release.html. Accessed April 26, 2006. International Code Council. 2003. International Plumbing Code, 2003 Edition. Falls Church, VA: International Code Council. Linn County. 2004. Linn County Plumbing Regulations. Available on-line at http://www.linncountyauditor.org/Ordinances/Plumbing--%5B5%5D.pdf. Accessed April 26, 2006. MacPhee, M. J. (ed.). 2005. Distribution system water quality challenges in the 21st century: a strategic guide. Denver, CO: AWWA. Martel, K. 2005. HACCP Applied to Distribution Systems. January 13, 2005. Presented to the NRC Committee on Public Water Supply Distribution Systems. Washington, DC. Martel, K., G. Kirmeyer, A. Hanson, M. Stevens, J. Mullenger, and D. Deere. 2006. Application of HACCP for Distribution System Protection. Denver, CO: AwwaRF. McCain, K., and M. Fahrenbruch. 2006. Succession planning: the babies and boomers. Source 20:16–17. Mucklow, R. 1997. Where did HACCP come from? In: Heads Up for HACCP. National Meat Association. Available on-line at http://www.nmaonline.org/files/headsup12-1.htm. Accessed May 4, 2006. National Aeronautics and Space Administration (NASA). 1991. A dividend in food safety. Spinoff 1991. NASA Technical Report ID 20020086314. Washington, DC: NASA. National Research Council (NRC). 2005. Public Water Supply Distribution Systems: Assessing and Reducing Risks, First Report. Washington, DC: National Academies Press. Pomerance, H., and E. G. Means. 2006. Succession planning: leveraging the inevitable. Source 20:10–13.
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Drinking Water Distribution Systems: Assessing and Reducing Risks State of Iowa. 2005. State Plumbing Code. Available on-line at http://www.legis.state.ia.us/Rules/2002/iac/641iac/64125/64125.pdf. Accessed April 26, 2006. World Health Organization (WHO). 2004. Guidelines for drinking water quality, third edition. Available on-line at http://www.who.int/water_sanitation_health/dwq/gdwq3/en/. Accessed April 26, 2006. Geneva, Switzerland: WHO.
Representative terms from entire chapter: