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Tap water quality report

Ontario, OH

EPA monitoring detected 14 contaminants across the 1 water supplier serving Ontario. A detection doesn't automatically mean the water is unsafe — see the level at the main supplier for each below, with its EPA source and period.

1
water supplier
6,756
people served
14
contaminants found
Ohio rankings Lead in Ohio PFAS in Ohio

What was found in Ontario's water

The level at the city's main supplier, the highest level anywhere in the city, the EPA limit for each, and where every figure comes from.

ContaminantLevel vs EPA limitSuppliersSource
Fluoride
1008 µg/L 25%
of the EPA limit 4000 µg/L
Main supplier: ONTARIO CITY · 6,756 people · 2019
1/1 SYR4
Copper
201.6 µg/L 16%
of the EPA limit 1300 µg/L
Main supplier: ONTARIO CITY · 6,756 people · 2019
1/1 SYR4
Barium
33.505 µg/L 1.7%
of the EPA limit 2000 µg/L
Main supplier: ONTARIO CITY · 6,756 people · 2019
1/1 SYR4
Lead
30.16 µg/L 201%
of the EPA limit, at the 95th percentile of samples — 15 µg/L
Main supplier: ONTARIO CITY · 6,756 people · 2019
1/1 SYR4
TTHM
29.15 µg/L 36%
of the EPA limit 80 µg/L
Main supplier: ONTARIO CITY · 6,756 people · 2019
1/1 SYR4
Lithium
14.3 µg/L
No EPA limit set
Main supplier: ONTARIO CITY · 6,756 people · 2023
1/1 UCMR-5
Chloroform
12.68 µg/L
No EPA limit set
Main supplier: ONTARIO CITY · 6,756 people · 2019
1/1 SYR4
Bromodichloromethane
8.84 µg/L
No EPA limit set
Main supplier: ONTARIO CITY · 6,756 people · 2019
1/1 SYR4
Dibromochloromethane
5.51 µg/L
No EPA limit set
Main supplier: ONTARIO CITY · 6,756 people · 2019
1/1 SYR4
Arsenic
3.6 µg/L 36%
of the EPA limit 10 µg/L
Main supplier: ONTARIO CITY · 6,756 people · 2019
1/1 SYR4
Bromoform
2.705 µg/L
No EPA limit set
Main supplier: ONTARIO CITY · 6,756 people · 2019
1/1 SYR4
Trichloroacetic Acid
1.4625 µg/L
No EPA limit set
Main supplier: ONTARIO CITY · 6,756 people · 2019
1/1 SYR4
Dichloroacetic Acid
1.295 µg/L
No EPA limit set
Main supplier: ONTARIO CITY · 6,756 people · 2019
1/1 SYR4
Lead
0.0027 mg/L 18%
of the EPA limit 0.0150 mg/L
Main supplier: ONTARIO CITY · 6,756 people · 2025
1/1 LCR
Each bar shows the measured level as a share of the EPA limit: green is well under, amber is close to it, red is over. For lead and copper the limit applies to exactly the 90th-percentile figure shown, so red there means a real exceedance. For everything else the limit applies to a running annual average while the figure is the 95th percentile of the system's samples — over 100% is worth reading, but is not by itself a violation. Formal violations are listed separately. These are the utilities' own EPA-reported results, not a city-wide average. A detection means the lab measured the substance — it isn't the same as exceeding a legal limit. Hover a source tag to see the EPA program and years behind each figure.

Water suppliers serving Ontario

SupplierPopulation served
ONTARIO CITY 6,756

Frequently asked questions about Ontario tap water

Is Ontario tap water safe to drink?

EPA testing detected 14 contaminants in the water serving Ontario. A detection isn't the same as a violation — most detected levels are within federal limits. Check the level and source for each contaminant above, and your utility's annual Consumer Confidence Report for the official compliance status.

How many water suppliers serve Ontario?

1 public water supplier report drinking-water monitoring for Ontario, Ohio to the EPA. Each is listed above with its population served.

What contaminants are in Ontario's water?

The contaminants EPA monitoring detected in Ontario include Fluoride, Copper, Barium, Lead, TTHM. The full list, with the level at the main supplier and the data source, is in the table above.

Where does this data come from?

Every figure is official EPA drinking-water monitoring — the Lead & Copper Rule, the UCMR-5 nationwide testing program, and the EPA Six-Year Review — not our own testing. Each number is labelled with its source and period.