SDWA Amendments of 1996

P.L. 104-182 (Aug. 6, 1996)

The occurrence of these chemicals in the drinking water supplies heightened public awareness. As a result, Congress passed the Safe Drinking Water Act of 1974. The drinking water regulations resulting from this Act were the first to apply to all public water systems in the United States, covering both chemical and microbial contaminants. Recall that, except for the coliform standard under the Interstate Quarantine Act of 1893, drinking water standards were not legally binding until the passage of the Safe Drinking Water Act of 1974. As shown in Table 5, the Act was amended several times, the last being 1996.

Highlights of the Safe Drinking Water Act

The most important of the safe drinking water acts are the Safe Drinking Water Act of 1974, the Safe Drinking Water Act Amendments of 1986, and the Safe Drinking Water Act of 1996. The Safe Drinking Water Act was first enacted on December 16, 1974 to protect public drinking water systems in the United States from harmful contaminants. The major provision of this Act requires the development of:

1. National primary drinking water regulations (Section 1412)

2. Underground injection control regulations to protect underground sources of drinking water (Section 1428)

3. Protection programs for sole-source aquifers (Section 1427)

Most notably, the 1986 amendments include:

1. Setting drinking water regulations for 83 specified contaminants by 1989

2. Establishment of requirements for disinfection and filtration of public water supplies and providing related technical assistance to small communities

3. Banning the use of lead pipes and lead solder in new drinking water distribution systems

4. Establishing an elective wellhead protection program around public water supply wells

5. Establishing an elective demonstration grant program for states and local authorities having designated sole-source aquifers to develop ground water protection programs

6. Issuing rules for monitoring wells that inject wastes below a drinking water source

Finally, the most notable highlights of the 1996 amendments include:

1. Requiring community water systems serving more than 10,000 customers to notify customers annually of the levels of federally regulated contaminants in the drinking water. These notifications must include information on the presence of suspicious but still unregulated substances. If a violation of the standard occurs, the notifications must contain information about the health effects of the contaminants in question.

2. Establishment of programs to train and certify competent water treatment plant operators

3. Establishment of key drinking water standards for Cryptosporidium, certain carcinogens, and other contaminants that threaten drinking water in the United States.

Development of MCLs and MCLGs

The Safe Drinking Water Act directs the EPA to develop national primary drinking water standards. These standard are designed to protect human health. In addition, secondary drinking water standards are developed to protect public welfare that deal primarily with contaminants affecting drinking water aesthetics such as odor, taste, and appearance. These standards are not federally enforceable and are issued only as guidelines. The primary drinking water standards are enforceable on all public water systems serving at least 25 persons.

With respect to setting standards, two terms have been invented: maximum contaminant level goals (MCLGs) and maximum contaminant levels (MCLs). MCLGs are health goals that are not enforceable. MCLs are the enforceable counterpart of the MCLGs. They are set as close to the MCLGs as feasible and are based upon treatment technologies, costs, and feasibility factors such as availability of analytical methods and treatment technology. For lead and copper, MCLGs and MCLs are not used; instead of specifying standards, water treatment is required.

The process of determining an MCL starts with an evaluation of the adverse effects caused by the chemical in question and the doses needed to cause such effects. The final result of this process is a safe dose that includes a margin of safety thought to provide protection against adverse effects. This dose is called a reference dose (Rf D) and is established based on the results of animal experiments. The research results are extrapolated to humans using standard EPA methods. This extrapolation varies depending upon whether the chemical is not a carcinogen, a known or probable carcinogen, or a possible carcinogen.

For chemicals that do not cause cancer, an MCLG is established by first converting the RfD to a water concentration. This number is then divided by five. The number five is based on the assumption that exposure to the chemical through drinking water represents only one-fifth of all the possible exposures to this substance. Other sources of exposure may include air, soil, and food. In most cases, the MCL established is the same value as the MCLG.

For a known or probable carcinogen, (EPA Class A or B), the MCLG is set at zero (i.e., no amount of chemical is acceptable). Because no analytical methods can measure zero, however, the MCL is based on the lowest concentration that can be measured on a routine basis. This is known as the practical quantitation limit (PQL). Thus, it is obvious that for known or probable carcinogens, the MCL is not guaranteed to be a safe level but instead is the lowest measurable level.

For possible cancer-causing chemicals (EPA Class C—some evidence exists that they may cause cancer, but it is not very convincing), a value equivalent to the MCLG is calculated as if they were not carcinogens. This value is then divided by a factor of ten to give the final MCL. Division by ten provides a margin of safety in case the chemical is later determined to be a carcinogen.

Drinking Water Regulations under the Act

In support of each regulation, Section 1412(b) of the Act requires that the EPA must make available to the public a document that specifies, to the extent practicable, the population addressed by the regulation. The document must state the upper, central, and lower estimates of risk and significant uncertainties and studies that would help resolve uncertainties. Finally, the document must include peer-reviewed studies that support or fail to support estimates.

Section 1412(b) further requires that whenever the EPA proposes a national primary drinking water regulation, it must publish a cost-benefit analysis. In the analysis for alternative MCLs, the effects on sensitive subpopulation must be considered; and in the analysis for treatment technique proposed for regulations, the cost and benefit factors required for an MCL regulation must be taken into account, as appropriate.

Section 1412(b)(6) requires that when the EPA proposes an MCL, it must publish a determination as to whether the costs of the standard are justified by the benefits. If the EPA determines that the costs of an MCL are not justified by the benefits, the law allows the EPA to set an MCL that maximizes health risk reduction benefits at a cost that is justified by the benefits. This section further limits the authority of the EPA to adjust the MCL from the feasible level if the benefits are justified for systems that serve 10,000 or more persons and for systems that are unlikely to receive a variance. This section further provides that the determination by the EPA as to whether or not the benefit of an MCL justifies the cost is judicially reviewable only as part of a court's review of the associated primary drinking water regulation.

Section 1412(b)(5) authorizes the EPA to consider "risk-risk" tradeoffs when setting an MCL. In other words, an MCL may be set at a level other than the feasible level if the technology to meet the MCL would increase health risk by (1) increasing concentration of other contaminants in drinking water, or (2) interfering with treatment used to comply with other primary drinking water regulations. When establishing such an MCL, the EPA shall (1) minimize overall risk by balancing both the risk reductions from treating the individual contaminant and possible side effects of such treatment on concentrations of other contaminants, and (2) assure that the combination of treatments for the individual contaminant and other contaminants shall not be more stringent than the "feasible."

Federal Financial Assistance

As discussed earlier under the Clean Water Act, the federal government has been giving grants for planning, design, and construction of municipal sewage treatment facilities in the form of revolving funds. Based on a similar concept, a State Revolving Fund (Section 1452) has been created to provide low interest loans to assist community and nonprofit noncommunity water systems in installing and upgrading treatment facilities. Part of this loan fund can be used to provide loan subsidies and loan forgiveness to poor communities. Also, based on seriousness of health risk, compliance needs, and system economic need, each year the states prepare plans identifying eligible projects and their priorities.

Federal and State Relationships

As in the Clean Water Act, federal jurisdiction is broad, but the states have the primary responsibility of enforcing the law (Section 1413) provided, however, that the EPA has determined that the state to enforce the law has adopted drinking water regulations that are no less stringent than the national primary drinking water regulations promulgated by the Administrator of the EPA. As a condition of primacy, states have the authority to impose administrative penalties. For example, for systems serving more than 10,000 persons, states are able to assess not less than $1,000 per day per violation. For smaller systems, states only have the authority adequate to ensure compliance. The EPA has the authority to take over the primacy, if the state fails to implement the authority given to it in the delegation.

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