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 and can pose a threat to ground water quality, if not managed properly. This website will provide information on recognizing the different types of Class V wells and the threats they pose. This website will also give you information about what you need to do if you own or operate one of these well types; how you can protect ground water; and where you can go, and who you can talk to if you want additional information.
Most Class V wells are shallow disposal systems that depend on gravity to drain fluids directly in the ground. There are over 20 well subtypes that fall into the Class V category and these wells are used by individuals and businesses to inject a variety of non-hazardous fluids underground. 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 that include storm water drainage wells, cesspools, and septic system leach fields. However, the Class V well category also includes more complex wells that are typically deeper and often used at commercial or industrial facilities.
Other more sophisticated Class V well types could include aquifer storage and recovery wells or geothermal electric power wells that are used to inject geothermal fluids extracted from subsurface hydrothermal systems. Complex Class V wells also include wells that are used to inject carbon dioxide (CO2) for long-term geologic sequestration. The CO2 geologic sequestration link below will provide background, and other information, including Class V Experimental Technology Well Guidance for Pilot Geologic Sequestration Projects.
Regardless of the use of a Class V well, owners and operators are responsible for protecting underlying ground water from contamination by the fluids they inject. Ninety percent of America's public water systems draw their water from ground water sources.
- Basic Information - Learn more about the uses and different types of Class V wells
- Well Types - Learn more about the different types of Class V wells
- Frequent Questions - Get answers to some basic questions about the Class V program
- Regulations - Read about EPA's Class V rules
- Guidance - Read EPA's guidances for Class V well owners and regulators
- How to Comply - Read about how to comply with various UIC rules
- Publications - See a list of available UIC fact sheets, guidances, studies, and videos
- Glossary - Find definitions of UIC-related terms