Is Cincinnati, OH Tap Water Safe? Quality & Contaminants

What was found in Cincinnati's water

The highest level seen across the city's suppliers, the EPA limit for each, and where the figure comes from.

Contaminant	Level vs EPA limit	Suppliers	Source
Nitrate	1910 µg/L 19% of the EPA limit 10000 µg/L	3/3	SYR4
Nitrate-Nitrite	1510 µg/L 15% of the EPA limit 10000 µg/L	3/3	SYR4
Copper	1302 µg/L 100% of the EPA limit, in the worst sample — 1300 µg/L	3/3	SYR4
Fluoride	1080 µg/L 27% of the EPA limit 4000 µg/L	3/3	SYR4
TTHM	75 µg/L 94% of the EPA limit 80 µg/L	3/3	SYR4
Barium	61.4 µg/L 3.1% of the EPA limit 2000 µg/L	3/3	SYR4
Lead	54.2 µg/L 361% of the EPA limit, in the worst sample — 15 µg/L	3/3	SYR4
Bromoform	41.1 µg/L No EPA limit set	3/3	SYR4
Chloroform	38.1 µg/L No EPA limit set	3/3	SYR4
Dibromochloromethane	26.5 µg/L No EPA limit set	3/3	SYR4
Bromodichloromethane	21.6 µg/L No EPA limit set	3/3	SYR4
Total Haloacetic Acids (HAA5)	20.2 µg/L 34% of the EPA limit 60 µg/L	3/3	SYR4
Dichloroacetic Acid	11.8 µg/L No EPA limit set	3/3	SYR4
Lithium	11.1 µg/L No EPA limit set	1/3	UCMR-5
Monobromoacetic Acid	10.1 µg/L No EPA limit set	2/3	SYR4
Dibromoacetic Acid	9.77 µg/L No EPA limit set	3/3	SYR4
Xylenes, Total	8.5 µg/L 0.1% of the EPA limit 10000 µg/L	1/3	SYR4
Arsenic	7.67 µg/L 77% of the EPA limit 10 µg/L	1/3	SYR4
Trichloroacetic Acid	6.78 µg/L No EPA limit set	2/3	SYR4
Monochloroacetic Acid	6.41 µg/L No EPA limit set	2/3	SYR4
Ethylbenzene	1.32 µg/L 0.2% of the EPA limit 700 µg/L	1/3	SYR4
Trichloroethylene	0.6900 µg/L 14% of the EPA limit 5 µg/L	1/3	SYR4
PFOS	0.0124 µg/L No EPA limit set	2/3	UCMR-5
Pfba	0.0057 µg/L No EPA limit set	2/3	UCMR-5
Pfpea	0.0048 µg/L No EPA limit set	1/3	UCMR-5
PFBS	0.0041 µg/L No EPA limit set	2/3	UCMR-5
Pfhxa	0.0030 µg/L No EPA limit set	1/3	UCMR-5
Lead	0.0021 mg/L 14% of the EPA limit 0.0150 mg/L	3/3	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 single worst sample on record — 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 Cincinnati

Supplier	Population served
CINCINNATI PUBLIC WATER SYSTEM	750,200
INDIAN HILL CITY PWS	15,000
WYOMING CITY PWS	9,700

Frequently asked questions about Cincinnati tap water

Is Cincinnati tap water safe to drink?

EPA testing detected 28 contaminants in the water serving Cincinnati. 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 Cincinnati?

3 public water suppliers report drinking-water monitoring for Cincinnati, Ohio to the EPA. Each is listed above with its population served.

What contaminants are in Cincinnati's water?

The contaminants EPA monitoring detected in Cincinnati include Nitrate, Nitrate-Nitrite, Copper, Fluoride, TTHM. The full list, with the highest level found 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.