Ohio well water testing: what to test every year
Short answer: Ohio State University Extension says a private well should be tested at least once a year for total coliform bacteria, nitrate, pH and total dissolved solids or conductivity. Testing isn't required, so owners must find a lab, collect the sample and act on results. Contact your local health department about suspected contamination.
The U.S. Geological Survey estimated that about 1.86 million people in Ohio supplied their own household water in 2015. USGS says the most common source of self-supplied water is a well. [source] [source]
Annual tests (OSU Extension)
Water tests aren't required in Ohio, but OSU Extension says a private well should be tested at least once a year for:
- total coliform bacteria
- nitrate
- pH
- total dissolved solids (or conductivity) [source]
It says these four tests are reasonable in cost and show either good water or a problem that needs more specific testing. Keep yearly records to spot trends. [source]
Where to test
Owners are on their own to find a testing lab, collect a sample and act on the results. Use the lab's own bottle, follow its directions, and check its schedule, since some labs won't accept samples on Fridays or weekends. [source] Contact your local health department if you suspect contamination from leaking fuel tanks, landfills or chemical spills. [source]
County guides
No county pages for this state yet. Your local health department is the first stop, per EPA guidance. [source]
FAQ
What should Ohio well owners test for every year?
Ohio State University Extension says a private well should be tested at least once a year for total coliform bacteria, nitrate, pH and total dissolved solids or conductivity. Testing isn't required, so owners must find a lab, collect the sample and act on results. Contact your local health department about suspected contamination.
Is well water testing required in Ohio?
OSU Extension says water tests are not required for an existing private well, but it should be tested at least once a year.
Sources
- USGS – Estimated Use of Water in the United States, County-Level Data for 2015 (domestic self-supplied population) (accessed 2026-10-23)
- USGS – Domestic Water Use (accessed 2026-10-23)
- Ohio State University Extension (Ohioline) – Household Well Water Testing, AEX-314 (accessed 2026-10-23)
- US EPA – Protect Your Home's Water (accessed 2026-10-23)
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