Sole Source Aquifers


Aquifers and surface water are drinking water systems that may be impacted by development. The Safe Drinking Water Act of 1974 requires protection of drinking water systems that are the sole or principal drinking water source for an area and which, if contaminated, would create a significant hazard to public health.

Sole Source Aquifer designations are one tool to protect drinking water supplies in areas where alternatives to the groundwater resource are few, cost-prohibitive, or nonexistent. The designation protects an area's ground water resource by requiring U.S Environmental Protection Agency (EPA) review of any proposed projects within the designated area that are receiving federal financial assistance. All proposed projects receiving federal funds are subject to review to ensure they do not endanger the water source.

Resources to contact for further information include the local water department or authority, Regional or State EPA Offices, and the local or state department of natural resources.

Only for new construction and conversion activities does the sole source aquifer (SSA) authority apply. SSA information is available from the local planning agency, but is also listed on the homepage of the EPA Office of Ground Water and Drinking Water.

HUD Guidance

Does the project include any activities beyond acquisition, leasing, or rehabilitation of existing buildings?

If so, is the project located on a sole source aquifer? Review the EPA regional Sole Source Aquifer (SSA) maps to determine whether the project is within the boundaries of a designated SSA.

If so, do you have a memorandum of understanding (MOU) or working agreement with the EPA that excludes your project from further review?

If not, will the proposed project contaminate the aquifer and create a significant hazard to public health? Consult with your Regional EPA Office.  Your consultation request should include detailed information about your proposed project and its relationship to the aquifer and associated streamflow source area.  EPA will also want to know about water, storm water and waste water at the proposed project.  Follow your MOU or working agreement or contact your Regional EPA office for specific information you may need to provide.  EPA may request additional information if impacts to the aquifer are questionable after this information is submitted for review.

If so, work with the EPA to develop mitigation measures.

Compliance and Documentation

The environmental review record should contain one of the following:

  • Documentation, including a map, showing that the project site is not on a sole source aquifer
  • A determination that the project consists solely of acquisition, leasing, or rehabilitation of existing buildings
  • Documentation showing that a memorandum of understanding (MOU) or agreement with the EPA excludes your project from further review
  • Documentation that EPA has reviewed and commented on the proposed action within an SSA and a description of any mitigation measures, if necessary

View Sole Source Aquifers - Worksheet.

View Sole Source Aquifers - Partner Worksheet.