Questions and Answers about Sole Source Aquifers | Region 10 | US EPA

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Questions and Answers about Sole Source Aquifers

Q: What is a sole source aquifer?

A: A sole source aquifer (SSA) is an underground water supply designated by the Environmental Protection Agency (EPA) as the "sole or principal” source of drinking water for an area.

Q: What gives EPA the authority to designate these aquifers?

A: The program was established under Section 1424(e) the Safe Drinking Water Act of 1974. Although EPA can designate sole source aquifers on its own, agency policy is to make designations only in response to formal requests or "petitions" that contain sufficient technical information to evaluate whether the aquifer meets EPA's designation criteria.

Q: What criteria have to be met for a designation?

A: Based on the statutory language, major criteria to be considered by EPA are whether the aquifer is the sole or principal source of drinking water and whether contamination of the aquifer would create a significant hazard to public health. EPA has further interpreted “sole or principal” to mean that the aquifer must supply at least 50 percent of the drinking water to persons living over the aquifer; there should be no alternate and feasible sources of drinking water that could replace the aquifer. In addition, aquifer boundaries should be delineated based on sound science and the best available information. Petitions may be submitted for entire aquifers, aquifer systems (hydrogeologically connected aquifers), or part of an aquifer, if that part is hydrogeologically separate from the rest of the aquifer.

Q: If aquifers are under the land surface and can't be seen, how can the boundaries be defined?

A: Characterizing ground water resources is often difficult. Aquifer boundaries can be based on various factors such as the extent of aquifer materials, geologic structures, and/or ground water recharge or discharge areas. Hydrogeologists must rely on the best available data from relevant ground water studies and professional judgement when evaluating aquifer boundaries.

Q: Can the public participate in EPA's designation decision process?

A: Yes, the public can participate by attending EPA public meetings or hearings, or by providing written comments to EPA during a formal comment period. EPA's public comment period provides the opportunity to provide information to EPA on technical factors related to SSA designation criteria. Prior to the comment period, EPA prepares and makes available to the public a "support document" that outlines the technical and legal basis for a proposed designation.

Q: What happens after an aquifer is designated?

A: According to the Safe Drinking Water Act, projects that are to receive "federal financial assistance" and which have the potential to contaminate the aquifer "so as to create a significant hazard to public health" are subject to EPA review and approval.

Q: What does "federal financial assistance" mean?

A: Federal financial assistance can be any financial benefit provided directly as aid to a specific project, program, or action through a written agreement by a department, agency, or instrumentality of the federal government in any form including contracts, grants, and loan guarantees. Actions or programs carried out by the federal government directly or actions performed for the federal government by contractors (unless specifically for the purpose of providing financial assistance), are not considered federal financial assistance.

Q: Does EPA authority extend to projects funded entirely by state, local, or private entities, or those funded solely with federal funds for federal agencies, for example, projects within military bases or other federal facilities?

A: No, such projects are excluded from the project review process under the SSA protection program. Of course, projects undertaken with other funds would still have to comply with all relevant water quality requirements at the federal, state, or local level.

Q: Aren't existing ground water programs enough to protect an aquifer?

A: In many cases, existing regulations, practices, or policies are adequate to protect an aquifer from contamination. If EPA knows that mechanisms are in place to prevent aquifer contamination, they would not be reviewed by EPA, or they would be reviewed and approved without any additional conditions.

Q: Under what circumstances would EPA ask for additional conditions before approving federal funding?

A: EPA would ask for changes to a project only when it would pose a threat to public health by contaminating an aquifer to the point where a safe drinking water standard could be exceeded. Occasionally, weak ground water protection standards, poor project design, or site-specific concerns for ground water quality lead to specific EPA recommendations or requirements. However, if EPA decides that a particular project might harm public health, the funding applicant has the opportunity to modify the project. EPA can help by providing advice or technical assistance to the federal funding agency, project engineer, and funding applicant on just what must be done to make a project safe.

Q: Has EPA ever denied federal funding to a project?

A: Yes, there have been cases where federal funding has been denied when an applicant has been either unwilling or unable to modify a project to protect an aquifer. Such denials are rare, however, and may have been at the request of the local jurisdiction because of the project's potential to adversely impact public or private drinking water supplies.

Q: If EPA refuses to approve federal funding, is that decision final and will the project just be canceled?

A: Not necessarily. The project proponent can, if financially able, decide to go it alone without the federal funds. Or, the project can be improved to protect the aquifer. Or, EPA's determination can be appealed through judicial review in the U.S. Court of Appeals in the Ninth Circuit Court in San Francisco.

Q: What about projects that have received federal funding prior to the aquifer being designated. Will such projects be reviewed under the SSA protection program?

A: No. Project reviews under the SSA protection program are not retroactive. Any project where the funding was approved prior to a designation is not subject to review. However, if additional federal funds are requested to modify or expand the same project, then the use of the new funding could be evaluated.

Q: How does EPA find out about projects to review and doesn't the SSA protection program just add more "red tape" to the federal funding process?

A: EPA can learn of proposed projects through its own investigations, or from notification by various federal, state, local, or private entities. However, EPA relies primarily on Memorandums of Understanding (MOUs) with other federal funding agencies to identify projects for possible review. These MOUs help establish review responsibilities by outlining notification procedures and by listing specific types of projects which should or should not be referred to EPA. MOUs are used to screen out routine projects that would have little or no impact on an aquifer, to outline information needed by EPA to perform a review, or to describe specific ground water protection measures that must be met before a type of project can be funded. MOUs typically call for EPA to review projects within 30 days of notification which limits delays in project funding.

Q: Are there any regulations which require federal agencies to notify EPA about projects?

A: With the exception of federal SSA regulations that apply only to the Edwards Aquifer in Texas, there are no requirements that federal agencies notify EPA about projects. However, if EPA learns of projects on its own or from other sources, it has the authority under the Safe Drinking Water Act to review them.

Q: What are some examples of projects that EPA typically reviews and what agencies fund them?

A: EPA has reviewed major highway improvement projects (USDOT - Federal Highway Administration); new transit centers and park-and-ride lots (USDOT - Federal Transit Administration); public water supply improvements, wastewater treatment facilities, and projects that involve animal wastes (USDA - Farm Service Agency); and housing subdivisions and other building construction projects that are not served by public water, sewer, and storm water drainage systems (Department of Housing and Urban Development and USDA - Rural Development).

Q: Does EPA review federally-assisted home mortgage loans, such as those offered through the VA or FHA?

A: EPA generally would not get involved if a private citizen were to seek such a loan to build a single family dwelling. However, EPA could get involved in reviewing a cluster of homes that were federally-assisted if they would collectively pose a threat to ground water quality. Unfortunately, there is no "magic number" when a collection of homes begins to pose a threat. This must be evaluated on a case-by-case basis and depends on several factors including local soil and geology, depth to ground water, density of the homes, and the type of water, sewage and storm water systems proposed. These factors help to estimate the volume and characteristics of pollutant sources, potential pathways to the aquifer, and thus possible impacts to public health.

Q: To what extent does EPA review agricultural projects?

A: EPA's role regarding agriculture and the SSA Program has traditionally been to coordinate with the USDA funding agency to ensure that existing federal, state, and local ground water quality measures are being followed. EPA may ask the funding agency to make sure that the applicant is aware of, and follows, the most appropriate agricultural management practices which are feasible.

Q: Given potential restrictions on projects, does SSA designation present an “unfunded mandate” or give EPA control over local land-use decisions and private property use?

A: No. EPA becomes involved only when the federal government has already been requested to be involved by providing some kind of financial assistance. The SSA protection program provides a kind of "liability insurance" for the government and taxpayers by ensuring that federal programs don't fund projects that cause a designated aquifer to become contaminated.

Q: But won't a sole source aquifer designation lead to increased environmental regulation from state and local governments?

A: Some states have adopted regulatory provisions that trigger more detailed environmental reviews for projects proposed over EPA-designated SSAs. For example, the State of Washington has additional siting requirements for municipal landfills and dangerous waste management facilities proposed over SSAs. In addition, sole source aquifers are sometimes identified as examples of areas that should be prioritized or managed for increased ground water protection efforts.

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