Summaries of Environmental Laws
Administered by the EPA
Congressional Research Service Report  RL30022
Redistributed as a service of the National Library for the Environment

Safe Drinking Water Act

Mary Tiemann, Specialist in Environmental Policy
Environmental Protection Section
Environment and Natural Resources Policy Division


Safe Drinking Water Act

National Drinking Water Regulations

Contaminant Selection
Standard Setting
Risk Assessment

State Primacy
Underground Injection Control
Ground Water Protection Grant Programs
Source Water Protection Programs

Safe Drinking Water Act

The Safe Drinking Water Act (SDWA), title XIV of the Public Health Service Act, is the key federal law for protecting public water systems from harmful contaminants. First enacted in 1974 and substantively amended in 1986 and 1996, the Act is administered through regulatory programs that establish standards and treatment requirements for drinking water, control underground injection of wastes that might contaminate water supplies, and protect ground water. The 1974 law established the current federal-state arrangement in which states may be delegated primary implementation and enforcement authority for the drinking water program; the 1986 amendments sought to accelerate contaminant regulation. The state-administered Public Water Supply Supervision (PWSS) program remains the basic program for regulating the Nation's public water systems.

The 104th Congress reauthorized and substantially revised the Act with the SDWA Amendments of 1996 (P .L. 104-182). Among other changes, the 1996 law adds flexibility to the Act's standard setting provisions, requires EPA to conduct cost-benefit analyses for most new standards, expands consumer information requirements, adds provisions to improve small system compliance and protect source waters, and authorizes a State Revolving Loan Fund (SRF) program to help public water systems finance projects needed to meet SDWA requirements. P.L. 104-182 extends authorizations for appropriations under the Act through FY2003.

Table 10. Safe Drinking Water Act and Amendments
(codified generally as 42 U.S.C. 300f-300j)

Year Act Public Law Number
1974 Safe Drinking Water Act of 1974 P.L. 93-523
1977 Safe Drinking Water Act Amendments of 1977 P.L. 95-190
1979 Safe Drinking Water Act Amendments P.L. 96-63
1980 Safe Drinking Water Act Amendments P.L. 96-502
1986 Safe Drinking Water Act Amendments of 1988 P.L. 99.339
1988 Lead Contamination Control Act of 1988 P.L. 100-572
1996 Safe Drinking Water Act Amendments of 1996 P.L. 104-182


As indicated by Table 10, the Safe Drinking Water Act has been amended several times since the original Safe Drinking Water Act of 1974 (P.L. 93-523). Congress enacted P.L. 93-523 after a nationwide study of community water systems revealed widespread water quality and health risk problems resulting from poor operating procedures, inadequate facilities, and poor management of public water supplies in communities of all sizes. The 1974 law gave EPA substantial discretionary authority to regulate drinking water contaminants and gave 8tates the lead role in implementation and enforcement.

The first major amendments (P.L. 99-339), enacted in 1986, were largely intended to increase the pace at which EPA regulated contaminants. These amendments required EPA to (1) issue regulations for 83 specified contaminants by June 1989 and for 25 more contaminants every three years thereafter, (2) promulgate requirements for disinfection and filtration of public water supplies, (3) ban the use of lead pipes and lead solder in new drinking water systems, (4) establish an elective wellhead protection program around public wells, (5) establish a demonstration grant program for state and local authorities having designated sole-source aquifers to develop groundwater protection programs, and (6) issue rules for monitoring injection wells that inject wastes below a drinking water source. The amendments also increased EPA's enforcement authority.

The Lead Contamination Control Act of 1988 (P.L. 100-572) added a new part F to the SDWA. Part F is intended to reduce exposure to lead in drinking water by requiring the recall of lead-lined water coolers, and requiring EPA to issue a guidance document and testing protocol to help schools and day care centers to identi~ and correct lead contamination in school drinking water.

After the 1986 Amendments proved to be too rigorous for EPA, states and pu~ic water systems, Congress made sweeping changes to the Act with the SDWA Amendments of 1996 (P.L. 104-182). Implementation of the 1986 provisions had brought to the fore wide dissatisfaction among states and communities with the Act (including related concerns involving regulatory flexibility, unfunded mandates, and cost-benefit analysis in standard setting). As over-arching themes, the 1996 Amendments target resources to address the greatest health risks, increase regulatory and compliance flexibility under the Act, and provide funding for federal drinking water mandates. Specific provisions revoked the requirement that EPA regulate 25 contaminants every 3 years, increased EPA's authority to consider costs when setting standards, authorized EPA to consider overall risk reduction, established a state revolving loan program to help communities meet compliance costs, and expanded the Act's focus on pollution prevention through a new source water protection program.

National Drinking Water Regulations

The Act instructs EPA on how to select contaminants for regulation and specifies how EPA must establish national primary drinking water regulations once a contaminant has been selected (Section 1412). As of late 1996, EPA had promulgated 84 drinking water regulations.

Contaminant Selection. P.L. 104-182 establishes a new process for EPA to select contaminants for regulatory consideration based on occurrence, health effects, and meaningful opportunity for health risk reduction. By February 1998 and every 5 years thereafter, EPA must publish a list of contaminants that may warrant regulation. Starting in 2001, and every 5 years thereafter, EPA must determine whether or not to regulate at least 5 of the listed contaminants. The Act directs EPA to evaluate contaminants that present the greatest health concern and to regulate contaminants that occur at concentration levels and frequencies of public health concern. The law also includes a schedule for EPA to complete regulations for disinfectants and disinfection byproducts (D!DBPs) and Cryptosporidium (a waterborne pathogen).

Standard Setting. Developing national drinking water regulations is a two-part process. For each contaminant that EPA has determined merits regulation, EPA must set a nonenforceable maximum contaminant level goal (MCLG) at a level at which no known or anticipated adverse health effects occur and which allows an adequate margin of safety. EPA must then set an enforceable standard, a maximum contaminant level (MCL), as close to the MCLG as is "feasible" using best technology, treatment techniques, or other means available (taking costs into consideration). Standards are generally based on technologies that are affordable for large communities; however, under P.L. 104-182, each regulation establishing an MCL must list any technologies, treatment techniques or other means that comply with the MCL and that are affordable for three categories of small public water systems.

The 1996 Amendments authorize EPA to set a standard at other than the feasible level if the feasible level would lead to an increase in health risks by increasing the concentration of other contaminants or by interfering with the treatment processes used to comply with other SDWA regulations. In such cases, the standard or treatment techniques must minimize the overall health risk. Also, when proposing a regulation, EPA must now publish a determination as to whether or not the benefits of the standard justify the costs. If EPA determines that the benefits do not justily the costs, EPA may, with certain exceptions, promulgate a standard that maximizes health risk reduction benefits at a cost that is justified by the benefits.

Risk Assessment. P.L. 104-182 adds risk assessment and communication provisions to SDWA. When developing regulations, EPA is now required to: (1) use the best available, peer-reviewed science and supporting studies and data; and (2) make publicly available a risk assessment document that discusses estimated risks, uncertainties, and studies used in the assessment. When proposing drinking water regulations, EPA must publish a health risk reduction and cost analysis. The law permits EPA to promulgate an interim standard without first preparing a benefit-cost analysis or making a determination as to whether the benefits of a regulation would justify the costs if EPA determines that a contaminant presents an urgent threat to public health.

New regulations generally become effective 3 years after promulgation. Up to 2 additional years may be allowed if EPA (or a state in the case of an individual system) determines the time is needed for capital improvements. Section 1412 includes specific provisions for arsenic, sulfate and radon.

The law authorizes states to grant Systems variances from a regulation if raw water quality prevents meeting the standards despite application of best technology (Section 1415). A new provision authorizes small system variances based on best affordable technology. States may grant these variances to systems serving 3,300 or fewer persons if the system cannot afford to comply (through treatment, an alternative water source, or restructuring) and the variance ensures adequate protection of public health; states may grant variances to systems serving between 3,300 and 10,000 persons with EPA approval. To receive a small system variance, the system must install a variance technology identified by EPA. The variance technology need not meet the MCL, but must protect public health. By August 1998, EPA must identify variance technologies for existing regulations. Variances are not available for microbial contaminants.

The Act also provides for exemptions if a regulation cannot be met for other compelling reasons (including costs) and if the system was in operation before the effective date of a standard or treatment requirement (Section 1416). An exemption is intended to give a public water system more time to comply with a regulation and can be issued only if it will not result in an unreasonable health risk. Small systems may receive exemptions for up to 9 years.

State Primacy

The primary enforcement responsibility for public water systems lies with the states, provided they adopt regulations as stringent as the national requirements, adopt authority for administrative penalties, develop adequate procedures for enforcement, maintain records, and create a plan for providing emergency water supplies (Section 1413). Currently, 55 of 57 states and territories have primacy authority. P.L. 104-182 authorizes $100 million annually for EPA to make grants to states to carry out the public water system supervision program. States may also use a portion of their SRF grant for this purpose (Section 1443).

Whenever EPA finds that a public water system in a state with primary enforcement authority does not comply with regulations, the Agency must notify the state and the system and provide assistance to bring the system into compliance. If the state fails to commence enforcement action within 30 days after the notification, EPA is authorized to issue an administrative order or commence a civil action. In a nonprimacy state, EPA must noti~ an elected local official (if any has jurisdiction over the water system) before commencing an enforcement action against the system (Section 1414).

Primacy states may establish alternative monitoring requirements to provide interim monitoring relief for systems serving 10,000 or fewer persons for most contaminants, if a contaminant is not detected in the first quarterly sample. States with approved source water protection programs may adopt alternative monitoring requirements to provide permanent monitoring relief to qualified systems for chemical contaminants (Section 1418).

P.L. 104-182 requires states to adopt programs for training and certif~ng operators of community and nontransient noncommunity systems. EPA must publish guidelines specifying minimum standards for operator certification by February 1999. Two years thereafter, EPA must withhold 20% of a state's SRF grant unless the state has an operator certification program (Section 1419).

States are also required to establish capacity development programs based on EPA guidance. State programs must include: 1) legal authority to ensure that new systems have the technical, financial, and managerial capacity to meet SDWA requirements; and 2) a strategy to assist existing systems that are experiencing difficulties to come into compliance. Beginning in FY2001, EPA is required to withhold a portion of SRF grants from states that do not have compliance development strategies (Section 1420).

Underground Injection Control

Another provision of the Act requires EPA to promulgate regulations for state underground injection control (UIC) programs to protect underground sources of drinking water. These regulations contain minimum requirements for the underground injection of wastes in five well classes to protect underground sources of drinking water and to require that a state prohibit, by December 1977, any underground injection that was not authorized by state permit (Section 1421). However, the regulations cannot interfere with the underground injection of brine from oil and gas production or secondary or tertiary recovery of oil unless underground sources of drinking water would be affected by that injection. By June 1975, EPA was required to publish a list of states for which an UIC program was thought necessary to protect drinking water supplies (Section 1422). Within 270 days of issuance of the regulations by EPA, the states were to provide evidence of a procedure to implement an underground injection control program. The Agency was required to approve or disapprove (in whole or in part) the state plans within 3 months of submission; if approved, the states would assume primary responsibility for enforcement. If EPA disapproves a state's plans, or the state chooses not to assume program responsibility, then EPA must implement the program (Section 1423). In areas that overlie a sole-source potable aquifer, EPA may prohibit new underground injection wells or disallow any Federal funding for projects that may threaten these aquifers (Section 1424(e)). For oil and gas injection operations only, states are delegated primary enforcement authority (when they have control programs) without meeting EPA regulations (Section 1425).

Ground Water Protection Grant Programs

The Act contains three additional ground water protection programs. Added in 1986, Section 1427 established procedures for demonstration programs to develop, implement, and assess critical aquifer protection areas already designated by the Administrator as sole source aquifers. Section 1428, also added in 1986, established an elective state program for protecting wellhead areas around public water system wells. If a state established a wellhead protection program by 1989, and EPA approved the state's program, then EPA may award grants covering between 50% and 90% of the costs of implementing the program. Section 1429, added by P.L. 104-182, authorizes EPA to make 50% grants to states to develop programs to ensure coordinated and comprehensive protection of ground water within the states. Appropriations for these three programs and for LYIC state program grants are authorized through FY2003.

Source Water Protection Programs

P.L. 104-182 broadens the pollution prevention focus of the Act to embrace surface water as well as ground water protection. New Section 1453 directs EPA to publish guidance for states to implement source water assessment programs that delineate boundaries of assessment areas from which systems receive their water, and identify the origins of contaminants in delineated areas to determine systems' susceptibility to contamination. States with approved assessment programs may adopt alternative monitoring requirements to provide systems with monitoring relief under Section 1418.

New Section 1454 authorizes a source water petition program based on voluntary partnerships between state and local governments. States may establish a program under which a community water system or local government may submit a source water quality partnership petition to the state requesting assistance in developing a voluntary partnership to: (1) reduce the presence of contaminants in drinking water; (2) receive financial or technical assistance; and (3) develop a long-term source water protection strategy. This section authorizes $5 million each year for grants to states to support petition programs. Also, states may use up to 10% of their annual SRF capitalization grant for the source water assessment activities or for the petition program.

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