Missouri
Underground Injection Control Wells
The Missouri Department of Natural Resources says the state obtained primacy for its underground injection control (UIC) program from the U.S. Environmental Protection Agency (EPA), which funds it, and that under the Safe Drinking Water Act EPA sets minimum federal requirements for injection practices so that injection wells do not contaminate underground sources of drinking water. It says its Missouri Geological Survey is responsible for regulating or remediating two classes of wells, Class II and Class V.
In a Phase I ESA
ASTM E1527-21 does not name injection well records among its standard record sources. A Class V well can be an onsite disposal system, a drainage well or a well used in a cleanup, so an inventory entry can point to fluids put into the ground at a property. Five Missouri details shape how to read one.
- Class II wells are oil and gas injection wells. The department says oil and gas injection wells are regulated through the State Oil and Gas Council by the Missouri Geological Survey. Its oil and gas permits page names the injection wells it reviews as enhanced oil recovery, disposal and hydrocarbon storage wells. See Oil and Gas Permits.
- Every Class V well must be registered. The department describes Class V wells as wells that in general inject non-hazardous fluids into or above underground sources of drinking water, typically shallow onsite disposal systems. It says all of them must be registered with the Missouri Geological Survey, on the Class V Well Inventory form (MO 780-1774) for a new well or an existing one never inventoried.
- Remediation wells mark a cleanup. The department lists groundwater remediation wells, used in cleaning up contaminated sites, as Class V wells. Where injection is at a hazardous waste site, the department's Waste Management Program or Environmental Remediation Program approves the well; the Water Protection Program approves all others. If a remediation well is recorded at or near a property, look for the cleanup it served.
- Approval is split among offices. For Class V onsite wastewater systems with drainfield disposal, the department says the Water Protection Program permits those discharging 3,000 gallons a day or more, and the Department of Health and Senior Services or a county health department with the minimum state standards in its ordinance permits smaller ones. Single family homes and non-residential systems serving fewer than 20 people a day are excluded. The Missouri Geological Survey regulates how remediation wells are built.
- Other Class V types. The department lists mine backfill wells, aquifer recharge wells, stormwater drainage wells and improved sinkholes as Class V types the Water Protection Program permits. An improved sinkhole is one altered to control how surface water flows underground.
Where to look a site up
- The department's Underground Injection Control Wells page links a Class II Well Inventory and a Class V Well Inventory. It labels both November 2025, though their addresses carry other dates. This handbook has not opened either file.
- The department's Site-specific Wastewater Permits page holds electronic copies of every site-specific wastewater permit now in effect, which it says include underground injection control well permits. It can be searched by permit type, permit number, applicant or facility, county and effective date. The page says permits issued before April 24, 2026 were archived under the state's website content standards.
- The Geological Survey Program is at 573-368-2100 and geology@dnr.mo.gov. The Water Protection Program's Water Pollution Control Branch is at 573-751-1300 and cleanwater@dnr.mo.gov.
Getting the file
The Site-specific Wastewater Permits page says to submit a Sunshine Law request when a permit cannot be found there. The pages read do not give a records route for well registrations; the Sunshine Law request is the department's general route.
Sources
Missouri Department of Natural Resources pages, read October 16, 2026, no modified date shown: