Your county health department
Ohio doesn't run a statewide free testing program that we know of. Some county health departments test wells or sell kits, so call yours first.
Ohio's private well pageNitrate in Ohio well water, by county
Nitrate is worth checking in 4 of the 12 Ohio counties with 10 or more tested wells, and rare in the rest. A county's share tells you how likely a problem is nearby. Only a test of your own well tells you what's in it.
How Ohio compares with the rest of the country
Across Ohio, about 1 in 48 tested wells had nitrate over the EPA limit of 10 mg/L (7 of 335). Across all tested wells in the US it's about 1 in 12. That's less often than in the country as a whole. Counties still differ, so check yours below.
Why it matters: It's dangerous for babies under 6 months, because it keeps their blood from carrying enough oxygen.
Nitrate soaks down into groundwater from fertilizer, manure and septic systems.
Nitrate in tested wells, county by county
Share of each county's tested wells with at least one result over the EPA limit of 10 mg/L. Counties need 10 or more tested wells to be listed. Widespread means 15% or more, worth checking 5 to 15%, rare under 5%.
| County | Wells tested | Wells over the limit | Level |
|---|---|---|---|
| Champaign County | 10 | Worth checking | |
| Hamilton County | 13 | Worth checking | |
| Greene County | 15 | Worth checking | |
| Butler County | 51 | Worth checking | |
| Shelby County | 32 | Rare | |
| Preble County | 39 | Rare | |
| Geauga County | 22 | Rare | |
| Montgomery County | 22 | Rare | |
| Tuscarawas County | 18 | Rare | |
| Licking County | 16 | Rare | |
| Clark County | 15 | Rare | |
| Miami County | 13 | Rare |
40 more Ohio counties have 1 to 9 tested wells for nitrate, too few to rate.
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Where to get your well tested for nitrate in Ohio
A lab Ohio certifies
Ask for nitrate by name. Results from a certified lab count for a home sale or a loan.
Labs certified by Ohio (PDF)A mail-in kit
Fill the bottles at your kitchen tap and mail them back. We mark the kits that include nitrate.
Compare kitsKeep reading about wells in Ohio
- Well water testing in Ohio: how to get tested and what turns up statewide
- Nitrate in well water: where it comes from, what it does and how to remove it
- Arsenic in Ohio wells, by county
- Uranium in Ohio wells, by county
- Manganese in Ohio wells, by county
- Lead in Ohio wells, by county
Questions people ask about nitrate in Ohio
Is there nitrate in Ohio well water?
Nitrate is worth checking in 4 of the 12 Ohio counties with 10 or more tested wells, and rare in the rest. Across Ohio, about 1 in 48 tested wells had nitrate over the EPA limit of 10 mg/L (7 of 335). Across all tested wells in the US it's about 1 in 12. That's less often than in the country as a whole. Counties still differ, so check yours below.
Where can I get my well tested for nitrate in Ohio?
Use a lab certified by Ohio for drinking water, or a mail-in kit that includes nitrate from a certified lab. Some county health departments test wells too, so call yours first.
See Ohio's list of certified labs (a PDF list), or compare mail-in kits.
Where these numbers come from
- Lab tests: Water Quality Portal (USGS and EPA), well samples since 2000. A well counts as over if any of its tests was over the EPA limit of 10 mg/L. Wells tested for studies and monitoring, not a random sample of homes.
- Likely overstated: our own check of who tested the wells, when and where. How we check.
- State programs and links: Department of Health.