Underground Injection Control (UIC)

Class V Wells for Injection of Non-Hazardous Fluids into or Above Underground Sources of Drinking Water

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Use of Class V wells

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. This disposal can pose a threat to ground water quality if not managed properly.

The different types of Class V wells pose various threats. Most Class V wells are shallow disposal systems that depend on gravity to drain fluids directly in the ground. Over 20 well subtypes fall into the Class V category. 

EPA estimates that there are more than 650,000 Class V wells in operation nationwide. Most of these Class V wells are unsophisticated shallow disposal systems.  Examples include:

  • Storm water drainage wells
  • Septic system leach fields
  • Agricultural drainage wells

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Complex Class V wells 

""Your community may have industrial waste disposal wells, storm water drainage wells, large-capacity septic systems, and other Class V wells. They are regulated and are not allowed to endanger underground sources of drinking water.

EPA's regulations define Class V wells as injection wells not included in other well classes.  As a result, in addition to shallow wells, the Class V well category includes deep complex wells used at commercial and industrial facilities. Complex Class V well types may include:

  • Aquifer storage and recovery wells
  • Geothermal electric power wells
  • Experimental wells used for pilot geologic sequestration

Regardless of the use of Class V wells, owners and operators are responsible for protecting underlying ground water from contamination. 

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