What was found in Cincinnati'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.
| Contaminant | Level vs EPA limit | Suppliers | Source |
|---|---|---|---|
| Nitrate | 1390 µg/L 14% of the EPA limit 10000 µg/L Main supplier: CINCINNATI PUBLIC WATER SYSTEM · 750,200 people · 2019
Highest in the city: 1910 µg/L — INDIAN HILL CITY PWS · 15,000 people · 2019 | 3/3 | SYR4 |
| Nitrate-Nitrite | 1390 µg/L 14% of the EPA limit 10000 µg/L Main supplier: CINCINNATI PUBLIC WATER SYSTEM · 750,200 people · 2019 | 3/3 | SYR4 |
| Fluoride | 965 µg/L 24% of the EPA limit 4000 µg/L Main supplier: CINCINNATI PUBLIC WATER SYSTEM · 750,200 people · 2019
Highest in the city: 1072 µg/L — WYOMING CITY PWS · 9,700 people · 2018 | 3/3 | SYR4 |
| Copper | 43.515 µg/L 3.3% of the EPA limit 1300 µg/L Main supplier: CINCINNATI PUBLIC WATER SYSTEM · 750,200 people · 2019
Highest in the city: 1058.25 µg/L — INDIAN HILL CITY PWS · 15,000 people · 2019 | 3/3 | SYR4 |
| TTHM | 61.41 µg/L 77% of the EPA limit 80 µg/L Main supplier: CINCINNATI PUBLIC WATER SYSTEM · 750,200 people · 2019
Highest in the city: 67.66 µg/L — WYOMING CITY PWS · 9,700 people · 2019 | 3/3 | SYR4 |
| Barium | 40.5 µg/L 2% of the EPA limit 2000 µg/L Main supplier: CINCINNATI PUBLIC WATER SYSTEM · 750,200 people · 2019
Highest in the city: 56.96 µg/L — WYOMING CITY PWS · 9,700 people · 2018 | 3/3 | SYR4 |
| Bromoform | 21.29 µg/L No EPA limit set Main supplier: CINCINNATI PUBLIC WATER SYSTEM · 750,200 people · 2019
Highest in the city: 25.27 µg/L — WYOMING CITY PWS · 9,700 people · 2019 | 3/3 | SYR4 |
| Chloroform | 24.1 µg/L No EPA limit set Main supplier: CINCINNATI PUBLIC WATER SYSTEM · 750,200 people · 2019 | 3/3 | SYR4 |
| Dibromochloromethane | 21.4 µg/L No EPA limit set Main supplier: CINCINNATI PUBLIC WATER SYSTEM · 750,200 people · 2019 | 3/3 | SYR4 |
| Lead | 21.12 µg/L 141% of the EPA limit, at the 95th percentile of samples — 15 µg/L Main supplier: CINCINNATI PUBLIC WATER SYSTEM · 750,200 people · 2019 | 3/3 | SYR4 |
| Bromodichloromethane | 16.31 µg/L No EPA limit set Main supplier: CINCINNATI PUBLIC WATER SYSTEM · 750,200 people · 2019
Highest in the city: 16.86 µg/L — INDIAN HILL CITY PWS · 15,000 people · 2019 | 3/3 | SYR4 |
| Total Haloacetic Acids (HAA5) | 13.9 µg/L 23% of the EPA limit 60 µg/L Main supplier: CINCINNATI PUBLIC WATER SYSTEM · 750,200 people · 2019
Highest in the city: 16.56 µg/L — INDIAN HILL CITY PWS · 15,000 people · 2019 | 3/3 | SYR4 |
| Lithium | 11.1 µg/L No EPA limit set Highest in the city: WYOMING CITY PWS · 9,700 people · 2025 | 1/3 | UCMR-5 |
| Monobromoacetic Acid | 5.354 µg/L No EPA limit set Main supplier: CINCINNATI PUBLIC WATER SYSTEM · 750,200 people · 2019
Highest in the city: 9.2015 µg/L — INDIAN HILL CITY PWS · 15,000 people · 2019 | 2/3 | SYR4 |
| Xylenes, Total | 8.5 µg/L 0.1% of the EPA limit 10000 µg/L Highest in the city: WYOMING CITY PWS · 9,700 people · 2019 | 1/3 | SYR4 |
| Arsenic | 7.365 µg/L 74% of the EPA limit 10 µg/L Highest in the city: WYOMING CITY PWS · 9,700 people · 2019 | 1/3 | SYR4 |
| Dichloroacetic Acid | 6.6835 µg/L No EPA limit set Main supplier: CINCINNATI PUBLIC WATER SYSTEM · 750,200 people · 2019 | 3/3 | SYR4 |
| Dibromoacetic Acid | 6.2895 µg/L No EPA limit set Main supplier: CINCINNATI PUBLIC WATER SYSTEM · 750,200 people · 2019 | 3/3 | SYR4 |
| Monochloroacetic Acid | 3.282 µg/L No EPA limit set Main supplier: CINCINNATI PUBLIC WATER SYSTEM · 750,200 people · 2019
Highest in the city: 3.66 µg/L — INDIAN HILL CITY PWS · 15,000 people · 2019 | 2/3 | SYR4 |
| Trichloroacetic Acid | 3.326 µg/L No EPA limit set Main supplier: CINCINNATI PUBLIC WATER SYSTEM · 750,200 people · 2019
Highest in the city: 3.474 µg/L — INDIAN HILL CITY PWS · 15,000 people · 2019 | 2/3 | SYR4 |
| Ethylbenzene | 1.32 µg/L 0.2% of the EPA limit 700 µg/L Highest in the city: WYOMING CITY PWS · 9,700 people · 2019 | 1/3 | SYR4 |
| Trichloroethylene | 0.6900 µg/L 14% of the EPA limit 5 µg/L Highest in the city: WYOMING CITY PWS · 9,700 people · 2019 | 1/3 | SYR4 |
| PFOS | 0.0061 µg/L No EPA limit set Main supplier: CINCINNATI PUBLIC WATER SYSTEM · 750,200 people · 2024
Highest in the city: 0.0124 µg/L — INDIAN HILL CITY PWS · 15,000 people · 2023 | 2/3 | UCMR-5 |
| Pfba | 0.0052 µg/L No EPA limit set Main supplier: CINCINNATI PUBLIC WATER SYSTEM · 750,200 people · 2024
Highest in the city: 0.0057 µg/L — INDIAN HILL CITY PWS · 15,000 people · 2023 | 2/3 | UCMR-5 |
| Pfpea | 0.0048 µg/L No EPA limit set Highest in the city: INDIAN HILL CITY PWS · 15,000 people · 2023 | 1/3 | UCMR-5 |
| PFBS | 0.0041 µg/L No EPA limit set Main supplier: CINCINNATI PUBLIC WATER SYSTEM · 750,200 people · 2024 | 2/3 | UCMR-5 |
| Pfhxa | 0.0030 µg/L No EPA limit set Highest in the city: INDIAN HILL CITY PWS · 15,000 people · 2023 | 1/3 | UCMR-5 |
| Lead | 0.0021 mg/L 14% of the EPA limit 0.0150 mg/L Main supplier: CINCINNATI PUBLIC WATER SYSTEM · 750,200 people · 2026 | 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 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 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, Fluoride, Copper, 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.