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.
• 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 on Class I wells www.epa.gov/safewater/uic/wells_class1.html

Class II injection wells that are used in association with the production of oil or natural gas.

• More information on Class II wells www.epa.gov/safewater/uic/wells_class2.html

Class III injection wells that are used for solution mining.

• More information on Class III wells www.epa.gov/safewater/uic/wells_class3.html

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 on Class IV wells www.epa.gov/safewater/uic/wells_class4.html

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 on Class V wells www.epa.gov/safewater/uic/class5/index.html