Groundwater Discharge & Underground Injection Control (GWD/UIC)

More than 25 percent of Rhode Island's population depends on groundwater resources for their water supply and nearly two-thirds of the State's cities and towns depend solely on groundwater for their potable water needs. The Groundwater Discharge Program plays a role in the protection of these underground sources of drinking water by regulating the discharge to or above the ground surface of commercial and industrial wastewater and other fluids that have the potential to contaminate the State's groundwater resources.

The framework for the Groundwater Discharge Program is the RIDEM regulations, Groundwater Discharge Rules, which incorporate the regulatory requirements under the Federal Safe Drinking Water Act (SDWA) for UIC discharge systems including dry wells, galleys, drain fields or other subsurface systems and similar discharges to the ground surface ("daylighted" discharges), formerly managed under Groundwater Certification in the RIDEM Groundwater Quality Rules.

The Groundwater Discharge Rules combine review activities from the two former regulatory programs to provide a streamlined process for the regulated community. The rules do not differentiate between new and existing injection systems - all facility owners are required to apply for and gain approval of a groundwater discharge, prevent movement of any discharged fluid that may cause or contribute to a violation of a drinking water standard and comply with all other requirements of the rules. Groundwater Discharge Program activities include the review of applications and notifications related to groundwater discharge system activities, the issuance of registrations and approvals, review of facility operations pertaining to compliance issues (e.g. system installation and operation, effluent and groundwater quality monitoring) and oversight of groundwater discharge system closures.

Groundwater discharges originate from a variety of sources and may include treated process water from industrial or commercial activities, clean water injected to replenish aquifers or prevent salt water intrusion into fresh water aquifers, reinjection of groundwater from geothermal heating and cooling systems or to manage stormwater runoff from impervious surfaces. The application review and approval requirements protect the State's groundwater resources through managing and monitoring effluent quality before it is discharged into or onto the ground. Many facilities that receive approval under the Groundwater Discharge Rules perform on-going monitoring and reporting of effluent and groundwater quality to demonstrate that Federal and State Groundwater Quality Standards are not exceeded at the discharge point. Field inspections are conducted at regulated facilities to support discharge system closures and program compliance.

Several notable changes to the program include a requirement for licensed well drillers to complete all drilling of geothermal wells (To find out if a well driller is licensed in Rhode Island, please contact the Rhode Island Contractors’ Registration and Licensing Board at or (401) 921-1590.); a coordinated approach for the review of stormwater applications within the Office of Water Resources (where approval is required from multiple regulatory programs for the same activity, a waiver from the Groundwater Discharge Rules may apply); and a prohibition on the use of floor drains in areas used for manufacturing processes, chemical storage and handling areas, areas used for storage or maintenance of motor vehicles and any area located in the wellhead protection area of a community water supply well. This prohibition is largely the result of the 1999 Federal ban on Motor Vehicle Waste Disposal Wells, which have shown that the improper disposal of chemicals, solvents, oils and other commercial or industrial wastewaters onto or into the ground through the use of floor drains can be a major source of contamination of the State's groundwater resources. Floor drains from these areas must be connected only to a municipal sewer system, where allowed, or to a wastewater holding tank. All existing floor drains discharging to or below the ground surface must be closed under RIDEM Groundwater Discharge Program supervision.

Primary Resources

RIDEM Groundwater Discharge Program Contacts:

Other RIDEM Links: