Sole Source Aquifer Program
June 2001

The Sole Source Aquifer (SSA) Program is authorized by Section 1424(e) of the Safe Drinking Water Act of 1974 (Public Law 93-523, 42 U.S.C. 300 et. seq), which states:

"If the Administrator determines, on his own initiative or upon petition, that an area has an aquifer which is the sole or principal drinking water source for the area and which, if contaminated, would create a significant hazard to public health, he shall publish notice of that determination in the Federal Register. After the publication of any such notice, no commitment for federal financial assistance (through a grant, contract, loan guarantee, or otherwise) may be entered into for any project which the Administrator determines may contaminate such aquifer through a recharge zone so as to create a significant hazard to public health, but a commitment for federal assistance may, if authorized under another provision of law, be entered into to plan or design the project to assure that it will not so contaminate the aquifer".

The Environmental Protection Agency (EPA) defines a sole or principal source aquifer as one which supplies at least 50 percent of the drinking water consumed in the area overlying the aquifer. EPA guidelines also require that these areas have no alternative drinking water source(s) which could physically, legally, and economically supply all those who depend upon the aquifer for drinking water. For convenience, all designated sole or principal source aquifers are usually referred to simply as a "sole source aquifer".

Any person may apply for SSA designation. A "person" is any individual, corporation, company, association, partnership, state, municipality, or federal agency. A petitioner is responsible for providing EPA with hydrogeologic and drinking water usage data, and other technical and administrative information required for assessing designation criteria.

In 1987, EPA published the Sole Source Aquifer Designation Petitioner Guidance to assist those interested in preparing and submitting petitions to EPA regional offices. The document provides procedures and criteria for proposing aquifer boundaries, determining whether an aquifer is the sole or principal source of drinking water, and for evaluating alterative sources of drinking water.

In general, the designation decision process takes a minimum of six months from the time that the petitioner submits a complete petition to EPA. The process may take less or more time, depending on the technical complexity of the petition, and on the number of petitions that may be undergoing review within the EPA regional office at that time.

In New England, EPA requests that persons interested in filing a petition contact our office and set up a meeting with our staff. During the meeting, EPA will provide information about the benefits of the program, examples of past petitions and the types of information necessary for designation, and will discuss appropriate boundaries (based on your goals and the hydrogeology of the area) for the proposed Sole Source Aquifer.

Designation of an aquifer as a "sole source aquifer" provides additional protection to the aquifer by giving EPA authority to review all proposed federal financially assisted projects which have the potential to contaminate the SSA area. Proposed projects that are funded entirely by state, local, or private concerns are not subject to EPA review. The reviews are designed to reduce the risk of ground water contamination which could pose a health hazard to those who use it. Generally, project reviews have been conducted on projects associated with:

• highway improvements and new road construction
• airport expansions;
• transportation centers and maintenance facilities
• large developments receiving federal grants or loans
• large wastewater treatment facilities
• water system improvements
• new construction of rail lines

These reviews are not targeted for family residences or small scale development projects unless there is federal financial assistance and a substantial risk for contamination to the aquifer or to public water supplies within it.

EPA has developed Memorandums of Understanding (MOU) with federal funding agencies to establish review responsibilities under the SSA program and to list categories of project which should or should not be referred to EPA for review. The goal of the MOU is to assure that each project in the designated SSA area that is to receive federal financial assistance from the involved federal agency is designed and conducted in a manner that will prevent the introduction of contaminants into the aquifer in quantities that may create a significant hazard to the health of people who rely upon the aquifer. A summary of current MOUs developed between federal agencies and the New England Office is available. These MOUs are updated periodically to reflect changes in overall ground water protection through passage of new or revised state regulations and improved environmental design capability. EPA's New England Office plans to update its MOUs in the near future. The updated MOUs will likely reduce referral of many small-scale projects already subject to state regulation for EPA review.

Most projects referred to EPA for review meet all federal, state, and local ground water protection standards and are approved without any additional conditions being imposed. Occasionally, EPA may determine that the project poses a significant risk to human health through ground water contamination. EPA would then seek to jointly work with the involved federal agency and project proponent to modify the project proposal to better integrate protection of the ground water resource. This process may lead to changes in project design or the agreement to conduct additional pollution prevention activities as a condition of funding.

SSA designation increase the public's awareness of the nature and value of local ground water resources by demonstrating the link between an aquifer and a community's drinking water supply. Often, the realization that an area's drinking water originates from a vulnerable underground supply can lead to an increased willingness to protect it. The public also has an opportunity to participate in the SSA designation process by providing written comments to EPA or participating in an EPA-sponsored public hearing prior to the designation decision.

Important information on the boundaries, hydrogeologic materials, and water use patterns of an area's aquifer must be documented by a petitioner seeking SSA designation. Following EPA's technical review of a petition, this information is summarized by the agency in a technical support document that is made available for public review. Following designation, a Federal Register notice is published to announce and summarize the basis for EPA's decision.

Sole source aquifer designation provides only limited federal protection of ground water resources which serve as drinking water supplies. It is not a comprehensive ground water protection program. Protection of ground water resources can best be achieved through an integrated and coordinated combination of federal, state, and local efforts. For example, local wellhead protection programs designed and implemented by communities to protect the recharge areas of public water supply wells, should complement contaminant source controls and pollution prevention efforts being managed at various levels of government. Such coordination ensures that all ground water activities meet the same protection goal without duplication of time, effort, and resources.

Although designated aquifers have been determined to be the "sole or principal" source of drinking water for an area, this does not imply that they are more or less valuable or vulnerable to contamination than other aquifers which have not been designated by EPA. Many valuable and sensitive aquifers have not been designated simply because nobody has petitioned EPA for such status or because they did not qualify for designation due to drinking water consumption patterns over the entire aquifer area. Furthermore, ground water value and vulnerability can vary considerably both between and within designated aquifers. As a result, EPA does not recommend using SSA status as the sole or determining factor in making land use decisions that may impact ground water quality. Rather, site-specific hydrogeological assessments should be considered along with other factors such as project design, construction practices, and long-term management of the site.

The State of Massachusetts provides added protection for Sole Source Aquifers [310 CMR 16.40 (3a)6]against potential contamination from solid waste facilities and underground storage tanks. Solid waste facilities may not be located in a Sole Source Aquifer unless there are no existing or potential public or private water supplies downgradient of the site and there are alternative existing or potential public water supplies available to meet the town's needs.

New or expanded underground storage tanks for non-residential purposes must meet enhanced construction specifications and have a mechanism for leak detection.