CT ECO Basic Data Guide

Aquifer Protection Areas

Example of Aquifer Protection Areas


An aquifer protection area is categorized as either a preliminary (level B) or final (level A) aquifer protection area, depending on the quality of mapping. Preliminary mapping provides a general estimate of the area contributing ground water to the well field. Final mapping is based on extensive, site-specific, detailed modeling of the ground water flow system at the well field. For a given aquifer protection area, this information includes either the preliminary or more detailed final mapping. Aquifer protection areas are represented as polygon areas and mapped for use at 1:24,000 scale (1 inch = 2,000 feet).


Administered by the Connecticut Department of Energy and Environmental Protection, the Aquifer Protection Program provides primary protection for Connecticut’s high-yield public water supply well fields. The intent of this program is to protect the water supplies by identifying the land areas contributing ground water to the wells through detailed field work and ground-water flow modeling, and then by regulating land use within those areas. Municipalities adopt land use regulations for final aquifer protection areas. For example, land use involving hazardous materials within a designated aquifer protection area is strictly monitored and regulated.

Use Limitations

This information does not include protection areas for all public water supply wells in Connecticut. It only includes aquifer protection areas for public water supply wells located in Connecticut that are set in stratified drift and serve a residential population of 1,000 or more. It does not include protection areas for smaller stratified drift public water supply wells that serve less than 1,000 people. And it does not include protection areas for public water supply wells drilled into bedrock. Also, it does not include protection areas located in Connecticut that serve customers out of state.

Dataset Information

  • Status - This information is updated as needed to include the final mapping of aquifer protection areas as they are completed and as individual municipalities adopt land use regulations for the area.
  • Date of Data - Refer to the Citiation Publication date in the GIS Metadata for the date of the data currently available online.
  • Map Scale and Accuracy - The information meets horizontal National Map Accuracy Standards for 1:24,000-scale mapping (1 inch = 2,000 feet).

Additional Documentation

  • Aquifer Protection Areas - CT ECO Complete Resource Guide
  • GIS Metadata – Contains technical documentation describing the Aquifer Protection Area data and the data sources, process steps, and standards used to collect, digitize, and store this information in a geographic information system (GIS).


GIS Data Download

  • Aquifer Protection Area data is downloadable from DEEP GIS Data.
  • Connect GIS and AutoCAD software to this information online using the Water Resource Management CT ECO Map Service.