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privatewelldata / Counties / Ohio

Montgomery County, Ohio

Arsenic: 4 of 34 sampled wells (12%) above the EPA limit of 10 µg/L. Nitrate: 1 of 143 sampled wells (1%) above the EPA limit of 10 mg/L as N. Samples 1972-11-01 to 2020-11-03; updated 2026-10-18. Source: Water Quality Portal (USGS, EPA, NWQMC), siteType=Well.

What wells in this county have measured for arsenic and nitrate. A local picture only: test your own well to know your water.

Arsenic

4 of 34 sampled wells (12%) had a latest result above the EPA limit of 10 µg/L.

Median (latest per well)
0.3 µg/L
90th percentile
9 µg/L
Highest
16.2 µg/L
Non-detects
14 wells' latest result was "not detected" with no detection limit reported; they are counted as below the limit.
Samples
119, 1972-11-01 to 2020-11-03
Source
Water Quality Portal (USGS, EPA, NWQMC), siteType=Well, downloaded 2026-10-18

Nitrate

1 of 143 sampled wells (1%) had a latest result above the EPA limit of 10 mg/L as N.

Median (latest per well)
0.257 mg/L as N
90th percentile
2.711 mg/L as N
Highest
12 mg/L as N
Non-detects
31 wells' latest result was "not detected" with no detection limit reported; they are counted as below the limit.
Samples
269, 1972-11-01 to 2020-11-03
Source
Water Quality Portal (USGS, EPA, NWQMC), siteType=Well, downloaded 2026-10-18

Includes monitoring, research and private wells reported to the Water Quality Portal. Non-detects count only when the lab's detection limit is at or below the EPA limit. Method: data rules.

What to do next

  1. Test your own well. County numbers cannot tell you what is in your water. See which tests fit your well.
  2. Use a lab certified by Ohio. Certified labs in Ohio.
  3. Compare your results with the EPA limits (arsenic 10 µg/L, nitrate 10 mg/L as N). If a result is above a limit, contact your county or state health department.
  4. If a result is high: arsenic guide · nitrate guide · bacteria guide · salesperson checklist.
  5. Test again every year for bacteria and nitrate. Get a yearly reminder.