What was found in Westerville'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 |
|---|---|---|---|
| Fluoride | 1064.55 µg/L 27% of the EPA limit 4000 µg/L Main supplier: AQUA OHIO - BLACKLICK · 7,100 people · 2017
Highest in the city: 2227 µg/L — AQUA OHIO - TIMBERBROOK PW · 865 people · 2017 | 5/5 | SYR4 |
| Copper | 657 µg/L 51% of the EPA limit 1300 µg/L Main supplier: AQUA OHIO - BLACKLICK · 7,100 people · 2019 | 5/5 | SYR4 |
| Nitrate | 630 µg/L 6.3% of the EPA limit 10000 µg/L Highest in the city: AQUA OHIO - LAKE DARBY · 3,562 people · 2019 | 4/5 | SYR4 |
| Nitrate-Nitrite | 627 µg/L 6.3% of the EPA limit 10000 µg/L Highest in the city: AQUA OHIO - LAKE DARBY · 3,562 people · 2019 | 2/5 | SYR4 |
| Barium | 25.99 µg/L 1.3% of the EPA limit 2000 µg/L Main supplier: AQUA OHIO - BLACKLICK · 7,100 people · 2017
Highest in the city: 63 µg/L — AQUA OHIO - WORTHINGTON HILLS PWS · 2,500 people · 2017 | 5/5 | SYR4 |
| TTHM | 26.17 µg/L 33% of the EPA limit 80 µg/L Main supplier: AQUA OHIO - BLACKLICK · 7,100 people · 2019
Highest in the city: 49.87 µg/L — AQUA OHIO - WORTHINGTON HILLS PWS · 2,500 people · 2019 | 5/5 | SYR4 |
| Chloroform | 15.11 µg/L No EPA limit set Main supplier: AQUA OHIO - BLACKLICK · 7,100 people · 2019
Highest in the city: 20.98 µg/L — AQUA OHIO - TIMBERBROOK PW · 865 people · 2019 | 5/5 | SYR4 |
| Dibromochloromethane | 4.2 µg/L No EPA limit set Main supplier: AQUA OHIO - BLACKLICK · 7,100 people · 2019
Highest in the city: 17.6 µg/L — AQUA OHIO - WORTHINGTON HILLS PWS · 2,500 people · 2019 | 5/5 | SYR4 |
| Bromodichloromethane | 8.68 µg/L No EPA limit set Main supplier: AQUA OHIO - BLACKLICK · 7,100 people · 2019
Highest in the city: 16.555 µg/L — AQUA OHIO - WORTHINGTON HILLS PWS · 2,500 people · 2019 | 5/5 | SYR4 |
| Lead | 5.82 µg/L 39% of the EPA limit 15 µg/L Main supplier: AQUA OHIO - BLACKLICK · 7,100 people · 2019
Highest in the city: 15 µg/L — AQUA OHIO - WORTHINGTON HILLS PWS · 2,500 people · 2017 | 4/5 | SYR4 |
| Total Haloacetic Acids (HAA5) | 8.78 µg/L 15% of the EPA limit 60 µg/L Main supplier: AQUA OHIO - BLACKLICK · 7,100 people · 2019
Highest in the city: 10.345 µg/L — AQUA OHIO - TIMBERBROOK PW · 865 people · 2019 | 5/5 | SYR4 |
| Lithium | 9.4 µg/L No EPA limit set Highest in the city: AQUA OHIO - LAKE DARBY · 3,562 people · 2024 | 1/5 | UCMR-5 |
| Dichloroacetic Acid | 3.83 µg/L No EPA limit set Main supplier: AQUA OHIO - BLACKLICK · 7,100 people · 2019
Highest in the city: 6.54 µg/L — AQUA OHIO - TIMBERBROOK PW · 865 people · 2019 | 5/5 | SYR4 |
| Arsenic | 6.45 µg/L 65% of the EPA limit 10 µg/L Highest in the city: AQUA OHIO - LAKE DARBY · 3,562 people · 2019 | 2/5 | SYR4 |
| Bromoform | 0.5000 µg/L No EPA limit set Main supplier: AQUA OHIO - BLACKLICK · 7,100 people · 2019
Highest in the city: 6.01 µg/L — AQUA OHIO - WORTHINGTON HILLS PWS · 2,500 people · 2019 | 5/5 | SYR4 |
| Trichloroacetic Acid | 5.335 µg/L No EPA limit set Main supplier: AQUA OHIO - BLACKLICK · 7,100 people · 2019 | 5/5 | SYR4 |
| Dibromoacetic Acid | 1.3 µg/L No EPA limit set Main supplier: AQUA OHIO - BLACKLICK · 7,100 people · 2019
Highest in the city: 4.34 µg/L — AQUA OHIO - WORTHINGTON HILLS PWS · 2,500 people · 2019 | 5/5 | SYR4 |
| Combined Radium (-226 And -228) | 3.3 pCi/L 66% of the EPA limit 5 pCi/L Highest in the city: AQUA OHIO - LAKE DARBY · 3,562 people · 2017 | 1/5 | SYR4 |
| Monochloroacetic Acid | 3.2 µg/L No EPA limit set Highest in the city: AQUA OHIO - WORTHINGTON HILLS PWS · 2,500 people · 2019 | 1/5 | SYR4 |
| Lead | 0.0 mg/L 0% of the EPA limit 0.0150 mg/L Main supplier: AQUA OHIO - BLACKLICK · 7,100 people · 2023
Highest in the city: 0.0027 mg/L — AQUA OHIO - TIMBERBROOK PW · 865 people · 2025 | 5/5 | 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 Westerville
| Supplier | Population served |
|---|---|
| AQUA OHIO - BLACKLICK | 7,100 |
| AQUA OHIO - HUBER RIDGE PWS | 5,393 |
| AQUA OHIO - LAKE DARBY | 3,562 |
| AQUA OHIO - WORTHINGTON HILLS PWS | 2,500 |
| AQUA OHIO - TIMBERBROOK PW | 865 |
Frequently asked questions about Westerville tap water
Is Westerville tap water safe to drink?
EPA testing detected 20 contaminants in the water serving Westerville. 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 Westerville?
5 public water suppliers report drinking-water monitoring for Westerville, Ohio to the EPA. Each is listed above with its population served.
What contaminants are in Westerville's water?
The contaminants EPA monitoring detected in Westerville include Fluoride, Copper, Nitrate, Nitrate-Nitrite, Barium. 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.