Groundwater / Wellhead Protection Programs

The Department of Environmental Management administers a number of programs that address groundwater protection. The framework for these programs is the Office of Water Resources Groundwater Classification and Standards Program.

Under this program, the DEM Groundwater Quality Rules classify the state's groundwater resources into four classes and establish groundwater quality standards for each class. In addition, the Office of Water Resources administers two programs to regulate discharges to groundwater: the Onsite Wastewater Treatment System program (formerly the individual sewage disposal system program) and the Groundwater Discharge Program, which includes activities formerly managed under the Underground Injection Control (UIC) Program and the Groundwater Certification Program. The DEM Office of Waste Management also administers several programs to regulate existing and potential sources of groundwater contamination (e.g., underground storage tanks, solid waste facilities, and groundwater remediation).

Rhode Island Groundwater Notes:

  • The US Geological Survey has estimated that 27 million gallons per day of groundwater are used in the state for drinking water and other beneficial uses.
  • Groundwater supplies approximately 26% of the state's population with drinking water from public and private wells.
  • Approximately two-thirds of the state's municipalities rely on groundwater to a significant degree as a source of drinking water.
  • The state's most significant and productive aquifers are located in the glacial deposits of stratified drift (see map in Appendix 3 of the Groundwater Quality Rules). The fractured bedrock underlying the state is also an important aquifer providing drinking water to most private wells and small public water systems.
  • Groundwater in RI is generally free of pollutants. Over 90% of the state is classified as suitable for drinking water use without treatment.
  • The state's groundwater resources are considered vulnerable to contamination because of the generally shallow depth to groundwater, aquifer permeability and the absence of subsurface confining layers.
  • DEM has designated wellhead protection areas for all 686 public wells in RI identified as of June 2017. 155 of these are active community wells serving a residential population. DEM sets a high priority for source control and remediation efforts in wellhead protection areas.
  • The US Environmental Protection Agency has designated four sole source aquifers in RI: Block Island, Pawcatuck, Hunt-Annaquatucket-Pettaquamscutt, and Jamestown.

For more information, contact: Jonathan Zwarg,