Last checked:
Private wells in Missouri: labs, drillers and who to call
One place for Missouri well owners, buyers and the pros who work with them: the state's private well program, how to find a state-certified lab and a licensed well driller, and every Missouri page on this site. Every fact links to its source.
Missouri at a glance
- Who's on a well: USGS estimates about 821,000 people in Missouri supplied their own household water in 2015, about 14% of the state's population. Most of them use private wells.1
- Who tests: EPA rules for public water systems don't apply to private wells, so testing is up to the owner. CDC says to test at least once a year for total coliform bacteria, nitrates, total dissolved solids and pH, use a state-certified lab, and ask your health department what else to test for where you live.2
- Selling or buying a home: we haven't reviewed Missouri's home-sale testing or disclosure rules yet, so we don't say whether a test is required. Ask your agent or attorney and the state program below, and see the state table in our homebuyer's guide.
Who to contact
- State private well information: Missouri Department of Health and Senior Services: Private Drinking Water.3
- Licensed well drillers and pump installers: Missouri Department of Natural Resources: Wells and Drilling. Check a contractor's license before you hire.
- State-certified labs: the Missouri Department of Natural Resources certifies labs for drinking water testing. Find a certified drinking water lab (links). Many certified labs are city or industry labs that only test their own samples, so call before you send a sample.4
- Local help: CDC says local or state health or environmental departments often test for nitrates and coliform bacteria, should have a list of certified labs, and can help you understand your results.2
- EPA Safe Drinking Water Hotline: (800) 426-4791.2
County pages
We haven't published a Missouri county page yet. Until we do, the state contacts above and the guides below apply statewide.
Find a pro in Missouri
Our directory doesn't cover Missouri yet. Use the official driller and lab lookups above.
Guides for Missouri well owners
- Buying a home with a well (offer contingencies, which tests to order, and home-sale rules by state)
- Who regulates private wells?
- How often to test a private well
- Best way to test well water
- How to read your well water test results
- Arsenic in well water, nitrate, uranium and radon
- Getting a new well drilled
- Shock chlorinating a well
- For professionals: selling a home with a well (realtors) and homes with a well (home inspectors)
-
Dieter, C.A., and others, 2018, Estimated Use of Water in the United States County-Level Data for 2015 (ver. 2.0), U.S. Geological Survey data release (state totals of the county self-supplied domestic population). https://doi.org/10.5066/F7TB15V5 ↩
-
CDC, "Guidelines for Testing Well Water" (July 1, 2024). https://www.cdc.gov/drinking-water/safety/guidelines-for-testing-well-water.html ↩↩↩
-
U.S. EPA, "Private Drinking Water Well Programs in Your State" (state links; we updated links that had moved). https://www.epa.gov/privatewells/private-drinking-water-well-programs-your-state ↩
-
U.S. EPA, "State Certification Programs Certify Laboratories to Conduct Drinking Water Analyses" (August 2025). https://www.epa.gov/system/files/documents/2023-03/state-cert-programs-certify-labs-to-conduct-drinking-water-analyses.pdf ↩