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Water: Drinking Water Standards

GROUND WATER RULE: State Requirements for Protecting Public Ground Water Systems


EPA has the responsibility to develop a ground water rule which not only specifies the appropriate use of disinfection but, just as important, addresses other components of ground water systems to assure public health protection. Section 1412(b)(1)(A) of the Safe Drinking Water Act (SDWA) requires EPA to establish National Primary Drinking Water Regulations for contaminants that may have an adverse public health effect and that present a meaningful opportunity for health risk reduction. This general provision is supplemented with an additional requirement under Section 1412(b)(8) that EPA also develop regulations specifying the use of disinfectants for ground water systems as necessary. To meet these requirements EPA is working with stakeholders to develop a Ground Water Rule (GWR) proposal by March 1999, and a final rule by November 2000.


State requirements call for best management practices (BMPs) that can and do contribute significantly to the reduction of waterborne illness in the United States. However, the variability among State requirements and implementation of these practices is high from one State to another. Some states have comprehensive well construction requirements while others do not apply local hydrogeological criteria in the siting of a well. Disinfection in some form is a requirement in all but one State. However, the circumstances where disinfection is required are different for virtually every State. In combination, the State-to-State differences are clearly evident when considering the mix of all best management practices imposed on ground water systems.

The underlying objective of the GWR is to build upon successful State requirements and practices. As discussed above, some States rely heavily on disinfection, while others emphasize a BMP preventative approach, disinfecting only on a case by case basis. Still other States utilize significant components of both approaches. To the degree possible, EPA intends to strengthen what is in place, not replace it. This approach to developing the GWR requires an understanding of the existing state baseline requirements. A key aspect to understanding existing State requirements is to recognize that although many States appear to require similar BMPs, the nature, scope and detail of these requirements varies significantly between States. This variability is discussed in more detail below.


In 1995 and 1996, staff from all 50 state drinking water programs provided EPA with state statutes, regulations and guidance relating to the construction and operation of public ground water systems. They also reported the number of community, non-transient and transient water systems disinfecting in their state. From these data EPA categorized the requirements according to disinfection practices, well siting and construction specifications, and distribution system protection practices. In addition, four individual questions addressed the existence of a wellhead protection program, the requirement of a sanitary survey, operator certification and microbial monitoring at the wellhead. EPA prepared summaries of each state's requirements, which were then checked by state staff. A summary from the state of Missouri is attached as an example.

All 50 states' summaries are compiled in the document Ground Water Disinfection and Protective Practices in the United States (EPA 1996). Exhibit 1 from the document, Summary of State Requirements, Guidelines, and Recommendations, is also attached.


The following information on state requirements is summarized in the categories of disinfection, well construction and distribution system requirements.

Disinfection - Of the state required sanitation practices in place, disinfection shows the greatest state-to-state variability. Forty-nine state drinking water programs require disinfection of some sort, but when and where disinfection is required varies considerably. Nationally, 55% of community water systems, 28% of nontransient noncommunity water systems and 17% of transient noncommunity systems disinfect in the United States. Among the thirteen states that require Statewide disinfection for all systems, only two states varied from the disinfection requirement with disinfection based on the year of a water system's construction (e.g. disinfection for all systems built after 1971). The remaining thirty-six states establish specific disinfection requirements on a case-by-case basis. Among these thirty-six states, seven states impose a broad requirement for continuous disinfection. The broad requirement for the seven states include across the board disinfection for three states, two states with disinfection based on the public water systems' year of construction and two states with disinfection based only on population served.

The differences in state disinfection requirements result in much different rates of disinfection from one state to another. These differences depend mostly on the regulatory structure in each state and whether waiver provisions readily exist. For example, the percentages of community/non-transient /transient systems disinfecting in Rhode Island are 7%/1%/1%, respectively, while in Florida, Kansas, Kentucky and Texas the percentages are 100%/100%/100%. High disinfection rates (i.e., above 50%) are mostly confined to the 20 states that impose a broad requirement for continuous disinfection on water. Low to medium disinfection rates (i.e., below 50%) are found in the 29 states where disinfection is primarily a regulatory reaction to the discovery of total coliform contamination.

Well Construction - Well construction codes are one of the most widespread required state management practices. Forty-eight states require that water systems be constructed according to state codes. With one exception, this requirement is mandatory for all public water supplies, including non-transient and transient water supplies. Forty-seven states have minimum setback distances for microbial contaminants in their well codes. However, as the discussion below indicates, the particulars of these regulations can vary significantly.In addition, Twenty-four states consistently and five states sometimes use hydrogeological criteria in well construction codes. The remaining twenty one states do not appear to require consideration of hydrogeological criteria in the approval of the siting of a well. Those states that impose criteria give the regulatory agencies only general or vague authority to consider local hydrogeologic characteristics. For example, hydrogeology is commonly examined to determine the length of the casing and the extent of grouting since they are often dependent on the aquifer used and overlying materials. However, most states only require the most general consideration of such protective measures. As a whole, the specific requirements within each state code vary considerably.

Sanitary Surveys - All states except one conduct sanitary surveys. EPA did not request detailed information on sanitary surveys for this report, however, the U.S. General Accounting Office (GAO) reported in "Key Quality Assurance Program is Flawed and Underfunded" the results of their study on state sanitary surveys. Based on a nationwide questionnaire and a review of 200 sanitary surveys conducted in four states, GAO found that sanitary surveys were often deficient in how they are conducted, documented, and/or interpreted. Sanitary survey requirements and corrective actions were inconsistent among states. They found that regardless of systems' size, deficiencies previously disclosed frequently went uncorrected. The most common deficiency cited by states was inadequate cross-connection programs. In regards to the comprehensiveness of surveys, some key components or operations of water systems are regularly not evaluated. Many states do not evaluate water distribution systems, operators' qualifications, or other key aspects of systems' design and operations.

Prior to the Total Coliform Rule, states emphasized sanitary surveys at community water systems. The Total Coliform Rule (40 CFR §141.21(d)) requires that systems collecting fewer than 5 samples per month (population < 4,100) must undergo an initial sanitary survey by June 1994 for community systems, or June 1999 for noncommunity systems. Some states have been slow to implement this requirement because of resource constraints. Some state programs have legal authority to require corrective action for deficiencies noted in a sanitary survey. A number of states, however, do not appear to have distinct authority to require correction of significant defects. This is one of the deficiencies noted in the GAO report outlined above. States without enforcement authority can only make recommendations.

Exhibit 1 lists those states with cross connection, operator certification and wellhead monitoring practices. As with disinfection and sanitary surveys, these activities may be implemented at community water systems more frequently than at noncommunity systems.


Work with State and stakeholders to identify key BMP practices and requirements that are common among many States and significantly contributing to the strengths of State ground water strategy.

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