Class IV

Class IV wells inject hazardous or radioactive fluids into or above underground sources of drinking water. The EPA banned Class IV wells in 1984 because of the risks they pose to underground sources of drinking water. Currently, 32 waste cleanup sites contain 122 Class IV wells.1

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

While new wells of this class are banned, sometimes undocumented or previously unknown sites are discovered, and they are given this status. Sometimes hazardous waste is disposed of in a Class V well, which automatically changes its status from Class V to Class IV.


1. USEPA. (n.d.). Class IV shallow hazardous and radioactive injection wells. Retrieved 11/9/2020 from

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