What was found in Okoboji'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 | 650 µg/L 16% of the EPA limit 4000 µg/L Highest in the city: CENTRAL WATER SYSTEM · 25 people · 2014 | 1/2 | SYR4 |
| Nitrate | 300 µg/L 3% of the EPA limit 10000 µg/L Highest in the city: CENTRAL WATER SYSTEM · 25 people · 2019 | 1/2 | SYR4 |
| Copper | 201 µg/L 15% of the EPA limit 1300 µg/L Main supplier: OKOBOJI WATER SUPPLY · 776 people · 2017 | 1/2 | SYR4 |
| TTHM | 81 µg/L 101% of the EPA limit, at the 95th percentile of samples — 80 µg/L Main supplier: OKOBOJI WATER SUPPLY · 776 people · 2019
Highest in the city: 97 µg/L — CENTRAL WATER SYSTEM · 25 people · 2013 | 2/2 | SYR4 |
| Chloroform | 61 µg/L No EPA limit set Main supplier: OKOBOJI WATER SUPPLY · 776 people · 2019
Highest in the city: 74.85 µg/L — CENTRAL WATER SYSTEM · 25 people · 2013 | 2/2 | SYR4 |
| Barium | 60 µg/L 3% of the EPA limit 2000 µg/L Highest in the city: CENTRAL WATER SYSTEM · 25 people · 2014 | 1/2 | SYR4 |
| Total Haloacetic Acids (HAA5) | 48 µg/L 80% of the EPA limit 60 µg/L Main supplier: OKOBOJI WATER SUPPLY · 776 people · 2019
Highest in the city: 51.699999999999996 µg/L — CENTRAL WATER SYSTEM · 25 people · 2013 | 2/2 | SYR4 |
| Dichloroacetic Acid | 24.449999999999996 µg/L No EPA limit set Main supplier: OKOBOJI WATER SUPPLY · 776 people · 2019
Highest in the city: 28.849999999999998 µg/L — CENTRAL WATER SYSTEM · 25 people · 2013 | 2/2 | SYR4 |
| Trichloroacetic Acid | 24 µg/L No EPA limit set Main supplier: OKOBOJI WATER SUPPLY · 776 people · 2019 | 2/2 | SYR4 |
| Bromodichloromethane | 17.5 µg/L No EPA limit set Main supplier: OKOBOJI WATER SUPPLY · 776 people · 2019
Highest in the city: 18.849999999999998 µg/L — CENTRAL WATER SYSTEM · 25 people · 2013 | 2/2 | SYR4 |
| Lithium | 11 µg/L No EPA limit set Main supplier: OKOBOJI WATER SUPPLY · 776 people · 2025 | 1/2 | UCMR-5 |
| Lead | 8.99999999999999 µg/L 60% of the EPA limit 15 µg/L Main supplier: OKOBOJI WATER SUPPLY · 776 people · 2017 | 1/2 | SYR4 |
| Monochloroacetic Acid | 5.050000000000001 µg/L No EPA limit set Main supplier: OKOBOJI WATER SUPPLY · 776 people · 2019
Highest in the city: 6.199999999999996 µg/L — CENTRAL WATER SYSTEM · 25 people · 2013 | 2/2 | SYR4 |
| Dibromochloromethane | 3.2 µg/L No EPA limit set Main supplier: OKOBOJI WATER SUPPLY · 776 people · 2019
Highest in the city: 4 µg/L — CENTRAL WATER SYSTEM · 25 people · 2013 | 2/2 | SYR4 |
| Arsenic | 1 µg/L 10% of the EPA limit 10 µg/L Highest in the city: CENTRAL WATER SYSTEM · 25 people · 2014 | 1/2 | SYR4 |
| Dibromoacetic Acid | 1 µg/L No EPA limit set Highest in the city: CENTRAL WATER SYSTEM · 25 people · 2013 | 1/2 | SYR4 |
| Monobromoacetic Acid | 1 µg/L No EPA limit set Main supplier: OKOBOJI WATER SUPPLY · 776 people · 2019 | 1/2 | SYR4 |
| Dalapon | 0.5000 µg/L 0.3% of the EPA limit 200 µg/L Highest in the city: CENTRAL WATER SYSTEM · 25 people · 2017 | 1/2 | SYR4 |
| Atrazine | 0.1000 µg/L 3.3% of the EPA limit 3 µg/L Highest in the city: CENTRAL WATER SYSTEM · 25 people · 2017 | 1/2 | SYR4 |
| Pfba | 0.0092 µg/L No EPA limit set Main supplier: OKOBOJI WATER SUPPLY · 776 people · 2025 | 1/2 | UCMR-5 |
| Lead | 0.0010 mg/L 6.7% of the EPA limit 0.0150 mg/L Main supplier: OKOBOJI WATER SUPPLY · 776 people · 2023 | 1/2 | 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 Okoboji
| Supplier | Population served |
|---|---|
| OKOBOJI WATER SUPPLY | 776 |
| CENTRAL WATER SYSTEM | 25 |
Frequently asked questions about Okoboji tap water
Is Okoboji tap water safe to drink?
EPA testing detected 21 contaminants in the water serving Okoboji. 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 Okoboji?
2 public water suppliers report drinking-water monitoring for Okoboji, Iowa to the EPA. Each is listed above with its population served.
What contaminants are in Okoboji's water?
The contaminants EPA monitoring detected in Okoboji include Fluoride, Nitrate, Copper, TTHM, Chloroform. 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.