Class V

EPA regulations define wells that do not fit into any other category as Class V wells. As such, Class V contains both shallow and deep systems injecting fluids above, into and below underground sources of drinking water. These wells inject non-hazardous fluids underground. Some operational uses for Class V wells include storm water drainage wells, septic system leach fields, agricultural drainage wells, aquifer storage and recovery wells, and geothermal electric power wells. Class V are the most numerous regulated injection wells with over half a million wells in the United States.

2018 Injection Wells by Class

Injection Well ClassNumber of Injection WellsInjection Wells Inspected
Class I830453
Class II181,43184,317
Class III28,327406
Class IV12227
Class V531,1764,038
Class VI20

Source: EPA 816F19005 April 2020

The majority of the different kinds of Class V wells rely on gravity drainage. For example, gravity pulls fluids through floor drains to septic systems or dry wells in facilities such as gas stations, service stations, and car washes. Municipal storm drains that lead to dry wells also use gravity to pull water off roads.1

Due to the diversity of Class V wells, there is no standard construction or geological requirement. However, the well’s relationship or proximity to the aquifer influences how it should be managed. Because operations for Class V wells generally do not treat fluids before discharge or injection, proper management of these facilities is the only way to protect underground sources of drinking water.1

Class V EPA UIC Wells

1. USEPA. (n.d.). Class V wells for injection of non-hazardous fluids into or above underground sources of drinking water. Retrieved 11/9/2020 from

Images: “Graphic” by Top Energy Training