What was found in Duncan'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-Nitrite | 350 µg/L 3.5% of the EPA limit 10000 µg/L Main supplier: DUNCAN PUBLIC UTILITIES AUTHORITY · 23,000 people · 2019 | 1/1 | SYR4 |
| Fluoride | 280 µg/L 7% of the EPA limit 4000 µg/L Main supplier: DUNCAN PUBLIC UTILITIES AUTHORITY · 23,000 people · 2013 | 1/1 | SYR4 |
| Barium | 237 µg/L 12% of the EPA limit 2000 µg/L Main supplier: DUNCAN PUBLIC UTILITIES AUTHORITY · 23,000 people · 2013 | 1/1 | SYR4 |
| TTHM | 190.265 µg/L 238% of the EPA limit, at the 95th percentile of samples — 80 µg/L Main supplier: DUNCAN PUBLIC UTILITIES AUTHORITY · 23,000 people · 2019 | 1/1 | SYR4 |
| Copper | 132.19999999999993 µg/L 10% of the EPA limit 1300 µg/L Main supplier: DUNCAN PUBLIC UTILITIES AUTHORITY · 23,000 people · 2018 | 1/1 | SYR4 |
| Lead | 126.645 µg/L 844% of the EPA limit, at the 95th percentile of samples — 15 µg/L Main supplier: DUNCAN PUBLIC UTILITIES AUTHORITY · 23,000 people · 2018 | 1/1 | SYR4 |
| Chloroform | 112.19999999999999 µg/L No EPA limit set Main supplier: DUNCAN PUBLIC UTILITIES AUTHORITY · 23,000 people · 2019 | 1/1 | SYR4 |
| Total Haloacetic Acids (HAA5) | 77.89999999999998 µg/L 130% of the EPA limit, at the 95th percentile of samples — 60 µg/L Main supplier: DUNCAN PUBLIC UTILITIES AUTHORITY · 23,000 people · 2019 | 1/1 | SYR4 |
| Bromodichloromethane | 55.879999999999995 µg/L No EPA limit set Main supplier: DUNCAN PUBLIC UTILITIES AUTHORITY · 23,000 people · 2019 | 1/1 | SYR4 |
| Dibromochloromethane | 49.959999999999994 µg/L No EPA limit set Main supplier: DUNCAN PUBLIC UTILITIES AUTHORITY · 23,000 people · 2019 | 1/1 | SYR4 |
| Trichloroacetic Acid | 34.6 µg/L No EPA limit set Main supplier: DUNCAN PUBLIC UTILITIES AUTHORITY · 23,000 people · 2019 | 1/1 | SYR4 |
| Dichloroacetic Acid | 33.85 µg/L No EPA limit set Main supplier: DUNCAN PUBLIC UTILITIES AUTHORITY · 23,000 people · 2019 | 1/1 | SYR4 |
| Bromoform | 14.944999999999995 µg/L No EPA limit set Main supplier: DUNCAN PUBLIC UTILITIES AUTHORITY · 23,000 people · 2019 | 1/1 | SYR4 |
| Lithium | 14.2 µg/L No EPA limit set Main supplier: DUNCAN PUBLIC UTILITIES AUTHORITY · 23,000 people · 2024 | 1/1 | UCMR-5 |
| Gross Beta Particle Activity | 12.382 pCi/L No EPA limit set Main supplier: DUNCAN PUBLIC UTILITIES AUTHORITY · 23,000 people · 2018 | 1/1 | SYR4 |
| Dibromoacetic Acid | 12 µg/L No EPA limit set Main supplier: DUNCAN PUBLIC UTILITIES AUTHORITY · 23,000 people · 2019 | 1/1 | SYR4 |
| Monochloroacetic Acid | 4.9 µg/L No EPA limit set Main supplier: DUNCAN PUBLIC UTILITIES AUTHORITY · 23,000 people · 2019 | 1/1 | SYR4 |
| Monobromoacetic Acid | 2.65 µg/L No EPA limit set Main supplier: DUNCAN PUBLIC UTILITIES AUTHORITY · 23,000 people · 2019 | 1/1 | SYR4 |
| Combined Radium (-226 And -228) | 1.49 pCi/L 30% of the EPA limit 5 pCi/L Main supplier: DUNCAN PUBLIC UTILITIES AUTHORITY · 23,000 people · 2018 | 1/1 | SYR4 |
| Dalapon | 1.44 µg/L 0.7% of the EPA limit 200 µg/L Main supplier: DUNCAN PUBLIC UTILITIES AUTHORITY · 23,000 people · 2019 | 1/1 | SYR4 |
| Pfba | 0.0075 µg/L No EPA limit set Main supplier: DUNCAN PUBLIC UTILITIES AUTHORITY · 23,000 people · 2024 | 1/1 | UCMR-5 |
| Pfpea | 0.0038 µg/L No EPA limit set Main supplier: DUNCAN PUBLIC UTILITIES AUTHORITY · 23,000 people · 2024 | 1/1 | UCMR-5 |
| Pfhpa | 0.0034 µg/L No EPA limit set Main supplier: DUNCAN PUBLIC UTILITIES AUTHORITY · 23,000 people · 2024 | 1/1 | UCMR-5 |
| Pfhxa | 0.0033 µg/L No EPA limit set Main supplier: DUNCAN PUBLIC UTILITIES AUTHORITY · 23,000 people · 2024 | 1/1 | UCMR-5 |
| Lead | 0.0 mg/L 0% of the EPA limit 0.0150 mg/L Main supplier: DUNCAN PUBLIC UTILITIES AUTHORITY · 23,000 people · 2024 | 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 Duncan
| Supplier | Population served |
|---|---|
| DUNCAN PUBLIC UTILITIES AUTHORITY | 23,000 |
Frequently asked questions about Duncan tap water
Is Duncan tap water safe to drink?
EPA testing detected 25 contaminants in the water serving Duncan. 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 Duncan?
1 public water supplier report drinking-water monitoring for Duncan, Oklahoma to the EPA. Each is listed above with its population served.
What contaminants are in Duncan's water?
The contaminants EPA monitoring detected in Duncan include Nitrate-Nitrite, Fluoride, Barium, TTHM, Copper. 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.