What was found in Red Oak'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 | 7100 µg/L 71% of the EPA limit 10000 µg/L Main supplier: RED OAK WATER SUPPLY · 5,596 people · 2019 | 1/2 | SYR4 |
| Copper | 888.5999999999998 µg/L 68% of the EPA limit 1300 µg/L Main supplier: RED OAK WATER SUPPLY · 5,596 people · 2019 | 2/2 | SYR4 |
| Fluoride | 749.5 µg/L 19% of the EPA limit 4000 µg/L Main supplier: RED OAK WATER SUPPLY · 5,596 people · 2019 | 1/2 | SYR4 |
| Barium | 240.7 µg/L 12% of the EPA limit 2000 µg/L Main supplier: RED OAK WATER SUPPLY · 5,596 people · 2015 | 1/2 | SYR4 |
| TTHM | 5.807499999999999 µg/L 7.3% of the EPA limit 80 µg/L Main supplier: RED OAK WATER SUPPLY · 5,596 people · 2019
Highest in the city: 52.164999999999964 µg/L — SOUTHWEST REG WATER DISTRICT (RED OAK) · 3,500 people · 2019 | 2/2 | SYR4 |
| Chloroform | 1.945 µg/L No EPA limit set Main supplier: RED OAK WATER SUPPLY · 5,596 people · 2019
Highest in the city: 37.28699999999998 µg/L — SOUTHWEST REG WATER DISTRICT (RED OAK) · 3,500 people · 2019 | 2/2 | SYR4 |
| Total Haloacetic Acids (HAA5) | 5.762499999999999 µg/L 9.6% of the EPA limit 60 µg/L Main supplier: RED OAK WATER SUPPLY · 5,596 people · 2019
Highest in the city: 34.89999999999998 µg/L — SOUTHWEST REG WATER DISTRICT (RED OAK) · 3,500 people · 2019 | 2/2 | SYR4 |
| Dichloroacetic Acid | 1.738 µg/L No EPA limit set Main supplier: RED OAK WATER SUPPLY · 5,596 people · 2019
Highest in the city: 18.969999999999988 µg/L — SOUTHWEST REG WATER DISTRICT (RED OAK) · 3,500 people · 2019 | 2/2 | SYR4 |
| Lithium | 16 µg/L No EPA limit set Main supplier: RED OAK WATER SUPPLY · 5,596 people · 2025 | 1/2 | UCMR-5 |
| Bromodichloromethane | 2.08 µg/L No EPA limit set Main supplier: RED OAK WATER SUPPLY · 5,596 people · 2019
Highest in the city: 10.483999999999995 µg/L — SOUTHWEST REG WATER DISTRICT (RED OAK) · 3,500 people · 2019 | 2/2 | SYR4 |
| Lead | 7.479999999999999 µg/L 50% of the EPA limit 15 µg/L Main supplier: RED OAK WATER SUPPLY · 5,596 people · 2019 | 2/2 | SYR4 |
| Trichloroacetic Acid | 0.8300 µg/L No EPA limit set Main supplier: RED OAK WATER SUPPLY · 5,596 people · 2019
Highest in the city: 7.369499999999995 µg/L — SOUTHWEST REG WATER DISTRICT (RED OAK) · 3,500 people · 2019 | 2/2 | SYR4 |
| Monochloroacetic Acid | 3.676 µg/L No EPA limit set Main supplier: RED OAK WATER SUPPLY · 5,596 people · 2019
Highest in the city: 7.085 µg/L — SOUTHWEST REG WATER DISTRICT (RED OAK) · 3,500 people · 2019 | 2/2 | SYR4 |
| Dibromochloromethane | 1.8375000000000001 µg/L No EPA limit set Main supplier: RED OAK WATER SUPPLY · 5,596 people · 2019
Highest in the city: 4.900999999999999 µg/L — SOUTHWEST REG WATER DISTRICT (RED OAK) · 3,500 people · 2019 | 2/2 | SYR4 |
| Combined Radium (-226 And -228) | 3.1649999999999996 pCi/L 63% of the EPA limit 5 pCi/L Main supplier: RED OAK WATER SUPPLY · 5,596 people · 2018 | 1/2 | SYR4 |
| Selenium | 2.0700000000000003 µg/L 4.1% of the EPA limit 50 µg/L Main supplier: RED OAK WATER SUPPLY · 5,596 people · 2015 | 1/2 | SYR4 |
| Dibromoacetic Acid | 1.38 µg/L No EPA limit set Main supplier: RED OAK WATER SUPPLY · 5,596 people · 2019
Highest in the city: 1.9529999999999998 µg/L — SOUTHWEST REG WATER DISTRICT (RED OAK) · 3,500 people · 2019 | 2/2 | SYR4 |
| Bromoform | 0.7500 µg/L No EPA limit set Main supplier: RED OAK WATER SUPPLY · 5,596 people · 2019 | 2/2 | SYR4 |
| Atrazine | 0.3150 µg/L 11% of the EPA limit 3 µg/L Main supplier: RED OAK WATER SUPPLY · 5,596 people · 2018 | 1/2 | SYR4 |
| Lead | 0.0027 mg/L 18% of the EPA limit 0.0150 mg/L Main supplier: RED OAK WATER SUPPLY · 5,596 people · 2025 | 2/2 | 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 Red Oak
| Supplier | Population served |
|---|---|
| RED OAK WATER SUPPLY | 5,596 |
| SOUTHWEST REG WATER DISTRICT (RED OAK) | 3,500 |
Frequently asked questions about Red Oak tap water
Is Red Oak tap water safe to drink?
EPA testing detected 20 contaminants in the water serving Red Oak. 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 Red Oak?
2 public water suppliers report drinking-water monitoring for Red Oak, Iowa to the EPA. Each is listed above with its population served.
What contaminants are in Red Oak's water?
The contaminants EPA monitoring detected in Red Oak include Nitrate, Copper, Fluoride, Barium, 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.