What was found in Columbus'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 | 10600 µg/L 106% of the EPA limit, at the 95th percentile of samples — 10000 µg/L Main supplier: COLUMBUS PUBLIC WATER SYSTEM · 1,305,946 people · 2019 | 2/5 | SYR4 |
| Nitrate-Nitrite | 10600 µg/L 106% of the EPA limit, at the 95th percentile of samples — 10000 µg/L Main supplier: COLUMBUS PUBLIC WATER SYSTEM · 1,305,946 people · 2019 | 2/5 | SYR4 |
| Fluoride | 1010 µg/L 25% of the EPA limit 4000 µg/L Main supplier: COLUMBUS PUBLIC WATER SYSTEM · 1,305,946 people · 2019
Highest in the city: 1268.5 µg/L — TIMBERLAKE WATER SYSTEM · 1,600 people · 2017 | 2/5 | SYR4 |
| Copper | 79 µg/L 6.1% of the EPA limit 1300 µg/L Main supplier: COLUMBUS PUBLIC WATER SYSTEM · 1,305,946 people · 2017
Highest in the city: 561.1 µg/L — TIMBERLAKE WATER SYSTEM · 1,600 people · 2019 | 4/5 | SYR4 |
| TTHM | 77.305 µg/L 97% of the EPA limit 80 µg/L Main supplier: COLUMBUS PUBLIC WATER SYSTEM · 1,305,946 people · 2019
Highest in the city: 97.285 µg/L — LEONARD PARK PWS · 266 people · 2019 | 4/5 | SYR4 |
| Chloroform | 57.475 µg/L No EPA limit set Main supplier: COLUMBUS PUBLIC WATER SYSTEM · 1,305,946 people · 2019
Highest in the city: 78.905 µg/L — LEONARD PARK PWS · 266 people · 2019 | 4/5 | SYR4 |
| Total Haloacetic Acids (HAA5) | 49.045 µg/L 82% of the EPA limit 60 µg/L Main supplier: COLUMBUS PUBLIC WATER SYSTEM · 1,305,946 people · 2019
Highest in the city: 49.05 µg/L — SANITARY DISTRICT #4 · 8,575 people · 2019 | 3/5 | SYR4 |
| Lead | 3.155 µg/L 21% of the EPA limit 15 µg/L Main supplier: COLUMBUS PUBLIC WATER SYSTEM · 1,305,946 people · 2017
Highest in the city: 38.295 µg/L — LEONARD PARK PWS · 266 people · 2019 | 4/5 | SYR4 |
| Dichloroacetic Acid | 26.9 µg/L No EPA limit set Main supplier: COLUMBUS PUBLIC WATER SYSTEM · 1,305,946 people · 2019
Highest in the city: 27.185 µg/L — LEONARD PARK PWS · 266 people · 2019 | 4/5 | SYR4 |
| Barium | 16.5 µg/L 0.8% of the EPA limit 2000 µg/L Main supplier: COLUMBUS PUBLIC WATER SYSTEM · 1,305,946 people · 2019
Highest in the city: 26.195 µg/L — TIMBERLAKE WATER SYSTEM · 1,600 people · 2017 | 2/5 | SYR4 |
| Trichloroacetic Acid | 20.8 µg/L No EPA limit set Main supplier: COLUMBUS PUBLIC WATER SYSTEM · 1,305,946 people · 2019
Highest in the city: 25.6 µg/L — SANITARY DISTRICT #4 · 8,575 people · 2019 | 4/5 | SYR4 |
| Bromodichloromethane | 15.5 µg/L No EPA limit set Main supplier: COLUMBUS PUBLIC WATER SYSTEM · 1,305,946 people · 2019
Highest in the city: 18.4 µg/L — SANITARY DISTRICT #4 · 8,575 people · 2019 | 4/5 | SYR4 |
| Dibromoacetic Acid | 3.54 µg/L No EPA limit set Main supplier: COLUMBUS PUBLIC WATER SYSTEM · 1,305,946 people · 2019
Highest in the city: 11.13 µg/L — SANITARY DISTRICT #4 · 8,575 people · 2019 | 3/5 | SYR4 |
| Dibromochloromethane | 9.9 µg/L No EPA limit set Main supplier: COLUMBUS PUBLIC WATER SYSTEM · 1,305,946 people · 2019 | 4/5 | SYR4 |
| Monochloroacetic Acid | 8.36 µg/L No EPA limit set Main supplier: COLUMBUS PUBLIC WATER SYSTEM · 1,305,946 people · 2019 | 3/5 | SYR4 |
| Arsenic | 5.39 µg/L 54% of the EPA limit 10 µg/L Highest in the city: TIMBERLAKE WATER SYSTEM · 1,600 people · 2019 | 1/5 | SYR4 |
| Bromoform | 4 µg/L No EPA limit set Main supplier: COLUMBUS PUBLIC WATER SYSTEM · 1,305,946 people · 2019 | 3/5 | SYR4 |
| Monobromoacetic Acid | 2.27 µg/L No EPA limit set Highest in the city: SANITARY DISTRICT #4 · 8,575 people · 2019 | 1/5 | SYR4 |
| Atrazine | 1.35 µg/L 45% of the EPA limit 3 µg/L Main supplier: COLUMBUS PUBLIC WATER SYSTEM · 1,305,946 people · 2019 | 1/5 | SYR4 |
| Lasso | 0.3675 µg/L 18% of the EPA limit 2 µg/L Main supplier: COLUMBUS PUBLIC WATER SYSTEM · 1,305,946 people · 2019 | 1/5 | SYR4 |
| Simazine | 0.3020 µg/L 7.6% of the EPA limit 4 µg/L Main supplier: COLUMBUS PUBLIC WATER SYSTEM · 1,305,946 people · 2019 | 1/5 | SYR4 |
| Pfhxa | 0.0182 µg/L No EPA limit set Main supplier: COLUMBUS PUBLIC WATER SYSTEM · 1,305,946 people · 2024
Highest in the city: 0.0220 µg/L — SANITARY DISTRICT #4 · 8,575 people · 2024 | 2/5 | UCMR-5 |
| Pfba | 0.0170 µg/L No EPA limit set Main supplier: COLUMBUS PUBLIC WATER SYSTEM · 1,305,946 people · 2024 | 2/5 | UCMR-5 |
| Pfpea | 0.0142 µg/L No EPA limit set Main supplier: COLUMBUS PUBLIC WATER SYSTEM · 1,305,946 people · 2024
Highest in the city: 0.0170 µg/L — SANITARY DISTRICT #4 · 8,575 people · 2024 | 2/5 | UCMR-5 |
| PFBS | 0.0111 µg/L No EPA limit set Main supplier: COLUMBUS PUBLIC WATER SYSTEM · 1,305,946 people · 2024 | 2/5 | UCMR-5 |
| PFOA | 0.0053 µg/L No EPA limit set Main supplier: COLUMBUS PUBLIC WATER SYSTEM · 1,305,946 people · 2024
Highest in the city: 0.0072 µg/L — SANITARY DISTRICT #4 · 8,575 people · 2024 | 2/5 | UCMR-5 |
| Pfhpa | 0.0043 µg/L No EPA limit set Main supplier: COLUMBUS PUBLIC WATER SYSTEM · 1,305,946 people · 2024
Highest in the city: 0.0054 µg/L — SANITARY DISTRICT #4 · 8,575 people · 2024 | 2/5 | UCMR-5 |
| Lead | 0.0012 mg/L 8% of the EPA limit 0.0150 mg/L Main supplier: COLUMBUS PUBLIC WATER SYSTEM · 1,305,946 people · 2023
Highest in the city: 0.0018 mg/L — TIMBERLAKE WATER SYSTEM · 1,600 people · 2025 | 4/5 | 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 Columbus
| Supplier | Population served |
|---|---|
| COLUMBUS PUBLIC WATER SYSTEM | 1,305,946 |
| SANITARY DISTRICT #4 | 8,575 |
| TIMBERLAKE WATER SYSTEM | 1,600 |
| GALLOWAY WATER SYSTEM PWS | 350 |
| LEONARD PARK PWS | 266 |
Frequently asked questions about Columbus tap water
Is Columbus tap water safe to drink?
EPA testing detected 28 contaminants in the water serving Columbus. 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 Columbus?
5 public water suppliers report drinking-water monitoring for Columbus, Ohio to the EPA. Each is listed above with its population served.
What contaminants are in Columbus's water?
The contaminants EPA monitoring detected in Columbus 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.