Originally regulated under the Safe Drinking Water Act, an injection well is used to place fluids underground into porous geologic formations as regulated under the federal Clean Water Act 40 CFR 144. A well is a bored, drilled or driven shaft whose depth is greater than the largest surface dimension, a dug hole whose depth is greater than the largest surface dimension, an improved sinkhole or a subsurface fluid distribution system.

The Water Protection Program permits only Class V Underground Injection Control (UIC) wells. Entities use Class V wells to inject non-hazardous fluids underground or subsurface, into or above underground sources of drinking water. As all true groundwater in Missouri is considered potential drinking water, underground injection must be properly regulated to protect groundwater, and potentially drinking water, quality. Class V wells include stormwater drainage wells, septic and domestic system leach fields/ subsurface dispersal fields and other industrial subsurface discharges.

The permit application for UIC depends on the type of UIC activity. UIC wells must also be registered with the Missouri Geological Survey using the Class V Well Inventory Form MO 780-1774Additional information on UIC activities, contact the Operating Permits section at 573-522-4502.