Do operators of injection wells have to monitor the ground water near their wells?
Ground water monitoring requirements depend on the type of injection well. For deep injection wells, the benefits of monitoring are weighed against the risk of creating pathways of upward fluid migration. Most monitoring requirements for deep wells focus on ensuring that the wells are operating correctly and the fluid is staying in the injection zone. In some cases, monitoring of USDWs far above the injection zone is performed. The area being mined using Class III wells may be monitored to make sure contaminated fluids are not moving out of the mining zone. Ground water monitoring may also be required for Class V wells to ensure that fluids being injected do not endanger USDWs. Class VI wells require extensive and continuous monitoring of injected CO2 to ensure USDWs are not being contaminated. Any monitoring requirements are specified in a well’s operating permit.
