Underground Injection Control

The Division of Water reviews and permits the use of underground injection wells in Delaware.

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Underground injection wells are used to place fluid underground into porous geologic formations for storage or disposal. They are regulated by the state to protect drinking water under the Federal Safe Drinking Water Act and the state’s Environmental Protection Act.

Types of Injection Wells

There are six classes of underground injection wells. Permits are issued under the Delaware Regulations Governing Underground Injection Control (7 DE Admin. Code 7102).

Class I wells are used to inject hazardous and non-hazardous wastes into deep, confined rock formations. They are currently not permitted in Delaware.

Class II wells are used to inject fluids associated with oil and natural gas production. They are currently not permitted in Delaware.

Class III wells are used to inject fluids to dissolve and extract minerals. They are currently not permitted in Delaware.

Class IV wells are shallow wells used to dispose hazardous or radioactive wastes into or above a geologic formation that contains an underground source of drinking water.  They are not currently permitted in Delaware and are banned nationally, except for use as part of an EPA- or state-authorized ground water clean-up action.

Class V wells are used to inject non-hazardous fluids underground. Most Class V wells are used to dispose of wastes into or above underground sources of drinking water. These types of wells include stormwater drainage wells, septic system leach fields, and agricultural drainage wells. The Delaware permitting and regulation program is designed to ensure they are properly designed, installed and managed to protect drinking water.

Class VI wells are used to inject carbon dioxide (CO2) into deep rock formations. They are currently not permitted in Delaware.