Ohio has a substantial rural population relying on private wells, concentrated across the state’s agricultural regions as well as more rural parts of Appalachian Ohio. Private wells are not regulated under the federal Safe Drinking Water Act, and Ohio, like every state, leaves testing to the well owner.
Why test
None of the contaminants below have a reliable taste, smell, or color at concerning levels, so a well can seem completely normal while still testing positive for bacteria or nitrate.
What to test for
A baseline panel for an Ohio well should include:
- Total coliform bacteria and E. coli — a standard first check for well vulnerability, and worth repeating after flooding, which can affect shallow wells in low-lying areas.
- Nitrate — a documented concern in Ohio’s agricultural regions, tied to fertilizer and manure application; especially important for households preparing infant formula with well water.
- Arsenic — naturally occurring arsenic has been found in groundwater in some Ohio counties; it has no taste or odor at concerning levels.
- Lead — mainly relevant to household plumbing rather than the source water.
How often to test
EPA guidance recommends testing private wells for bacteria and nitrate at least annually, and again any time water quality changes noticeably, after well or plumbing work, or after nearby flooding.
Where to find a certified lab
Ohio EPA’s Division of Drinking and Ground Waters maintains a current list of laboratories certified or accepted to perform analyses on public and private drinking water samples, covering microbiological, chemical, and radiochemical testing — see the source link above for the current list (Ohio EPA’s main website was temporarily unreachable when this page was last verified; the list itself is hosted on the agency’s document server and was confirmed current as of this page’s last verification date).
After you test
If a result comes back above a health-based guideline, see our filter guides for which technologies are certified to remove the specific contaminant found.