Wells_Content Page_Underground injection wells

Underground injection wells

The Underground Injection Control (UIC) program is a requirement of the federal Safe Drinking Water Act of 1974. The purpose of the UIC program is to protect underground sources of drinking water (a.k.a. groundwater) from contamination that may result from the use of injection wells. Each state is required to establish a UIC regulatory program that enforces rules that are at least as stringent as those published in the Code of Federal Regulations. Any state that fails to establish its own UIC program will be subject to the direct enforcement of federal injection well regulations by the United States Environmental Protection Agency (EPA).

What is an “injection well”?

An injection well is any well that is used to place — or in any similar manner release, discharge or disperse — a fluid underground.

A well may be any of the following:

  • A bored, drilled or driven shaft;
  • A dug hole that is deeper than its widest cross surface dimension;
  • A sinkhole that is altered in any manner to receive any fluid or accept additional surface drainage; or
  • A subsurface fluid distribution system such as a septic system drainfield or any similar conveyance.

Federal regulations identify five classes of injection wells

  • Class I injection wells that place hazardous wastes, municipal wastewater or other industrial waste fluids deep underground. More information [exit DNR]
  • Class II injection wells that are used in association with the production of oil or natural gas. More information [exit DNR]
  • Class III injection wells that are used for solution mining. More information [exit DNR]
  • Class IV injection wells that place hazardous waste either above an aquifer or directly into any aquifer that is used as a source of drinking water. Class IV injection wells are banned nationwide. More information [exit DNR]
  • Class V injection wells that place other non-hazardous fluids either directly into or above any aquifer that may be used as an underground source of drinking water. More information [exit DNR]

Requirements for owners or operators of injection wells

  1. The owner or operator of any existing injection well must report the existence of the well to the state UIC authority. This requirement can be met in the State of Wisconsin by completing a one-page injection well inventory form and returning it to DNR’s Bureau of Drinking Water and Groundwater.
  2. The owner or operator of any existing injection well must operate the well in a manner that does not endanger any aquifer that may be affected by the operation of injection well.
  3. All new injection wells must be approved by the authority having jurisdiction prior to construction and must be reported to the DNR by means of a completed injection well inventory form.

Injection well topics of interest to Wisconsin residents

Wisconsin injection well regulations

» Chapter NR 815 [exit DNR], Wis. Admin. Code