Well water testing when you sell a home in Missouri
If your Missouri home is on a private well and your buyer is financing it, the well water almost always has to be tested. The test has to be done by a disinterested third party (the local health authority or a certified lab), not the buyer or seller. The Missouri State Public Health Laboratory does not do real-estate water tests, so a private certified lab handles it. The report can be up to 180 days old for FHA and USDA, and only 90 days old for VA.
Verified against the Missouri DHSS State Public Health Laboratory pages, HUD Handbook 4000.1, USDA HB-1-3555 Ch. 12, and VA Circular 26-17-19, 2026-09-10.
Who can test the water
- The local public health agency (county health department), or
- A state-certified laboratory, or a commercial lab that performs analyses for hire.
- Not the seller, buyer, agent, or any other interested party — for VA loans this is an explicit rule, and it is good practice for all of them.
The Missouri State Public Health Laboratory offers a low-cost coliform/E. coli test as a public-health service for homeowners, but it states plainly that it does not offer testing for real estate transactions. For a mortgage file you need a private lab. Ask your county health department, your lender, or call the EPA Safe Drinking Water Hotline (800-426-4791) for certified-lab referrals.
What is on the panel
- Bacteria — total coliform and E. coli (the core mortgage requirement).
- Nitrate / nitrite — commonly required; a high nitrate result is a real health concern for infants and usually needs treatment before closing.
- Lead, and sometimes arsenic — depending on the lender and the area. Some Missouri groundwater carries elevated arsenic; if a local advisory or your lender calls for it, an arsenic result can matter.
- The exact panel is set by the lender and, where one exists, the local health authority.
How recent the test has to be
| Loan | Maximum age of the water analysis |
|---|---|
| USDA (Rural Development) | 180 days at loan closing |
| FHA | 180 days at the disbursement date (only when a test is required) |
| VA | 90 days from the date the local health authority certifies it |
If the water fails
A failed bacteria test is often fixed with shock chlorination and a re-test. A high nitrate or other chemical result usually means a treatment system (and sometimes a permit), which takes longer — build that time into the closing schedule. The system that treats the water is a separate company from the lab that tests it.
The county rule can require a well inspection too. St. Charles County requires the private well to be inspected for compliance at transfer, alongside the septic system — see St. Charles County. Other launch counties are being confirmed.
Sources & last verified
- (“does not offer testing for real estate transactions”). Checked 2026-09-10.
- . Checked 2026-09-10.
- ; ; VA Circular 26-17-19 (see the current ). Checked 2026-09-10.
Corrections: corrections@homecleared.com.