What was found in Decorah'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 | 7400 µg/L 74% of the EPA limit 10000 µg/L Main supplier: DECORAH WATER DEPARTMENT · 7,615 people · 2019 | 1/5 | SYR4 |
| Fluoride | 1000 µg/L 25% of the EPA limit 4000 µg/L Main supplier: DECORAH WATER DEPARTMENT · 7,615 people · 2019 | 5/5 | SYR4 |
| Copper | 514 µg/L 40% of the EPA limit 1300 µg/L Main supplier: DECORAH WATER DEPARTMENT · 7,615 people · 2019 | 5/5 | SYR4 |
| Barium | 104.075 µg/L 5.2% of the EPA limit 2000 µg/L Main supplier: DECORAH WATER DEPARTMENT · 7,615 people · 2012 | 5/5 | SYR4 |
| Total Haloacetic Acids (HAA5) | 30.96 µg/L 52% of the EPA limit 60 µg/L Main supplier: DECORAH WATER DEPARTMENT · 7,615 people · 2019 | 3/5 | SYR4 |
| TTHM | 24.06 µg/L 30% of the EPA limit 80 µg/L Main supplier: DECORAH WATER DEPARTMENT · 7,615 people · 2019 | 3/5 | SYR4 |
| Monobromoacetic Acid | 16.8 µg/L No EPA limit set Main supplier: DECORAH WATER DEPARTMENT · 7,615 people · 2019 | 1/5 | SYR4 |
| Lead | 12.875 µg/L 86% of the EPA limit 15 µg/L Main supplier: DECORAH WATER DEPARTMENT · 7,615 people · 2019 | 5/5 | SYR4 |
| Chloroform | 12.78 µg/L No EPA limit set Main supplier: DECORAH WATER DEPARTMENT · 7,615 people · 2019 | 3/5 | SYR4 |
| Monochloroacetic Acid | 11.41 µg/L No EPA limit set Main supplier: DECORAH WATER DEPARTMENT · 7,615 people · 2019 | 3/5 | SYR4 |
| Dichloroacetic Acid | 10.574 µg/L No EPA limit set Main supplier: DECORAH WATER DEPARTMENT · 7,615 people · 2019 | 2/5 | SYR4 |
| Bromodichloromethane | 6.218 µg/L No EPA limit set Main supplier: DECORAH WATER DEPARTMENT · 7,615 people · 2019 | 3/5 | SYR4 |
| Trichloroacetic Acid | 1.987 µg/L No EPA limit set Main supplier: DECORAH WATER DEPARTMENT · 7,615 people · 2019
Highest in the city: 5.058 µg/L — DEERFIELD HEIGHTS ASSOCIATION · 28 people · 2018 | 3/5 | SYR4 |
| Dibromochloromethane | 4.062 µg/L No EPA limit set Main supplier: DECORAH WATER DEPARTMENT · 7,615 people · 2019 | 2/5 | SYR4 |
| Combined Radium (-226 And -228) | 3.34 pCi/L 67% of the EPA limit 5 pCi/L Highest in the city: SHERMAN PLACE WATER & ROAD, INC. · 73 people · 2019 | 4/5 | SYR4 |
| Antimony, Total | 2.4 µg/L 40% of the EPA limit 6 µg/L Main supplier: DECORAH WATER DEPARTMENT · 7,615 people · 2012 | 1/5 | SYR4 |
| Selenium | 2 µg/L 4% of the EPA limit 50 µg/L Main supplier: DECORAH WATER DEPARTMENT · 7,615 people · 2012 | 1/5 | SYR4 |
| Thallium, Total | 1.28 µg/L 64% of the EPA limit 2 µg/L Main supplier: DECORAH WATER DEPARTMENT · 7,615 people · 2012 | 1/5 | SYR4 |
| Bromoform | 1.19 µg/L No EPA limit set Main supplier: DECORAH WATER DEPARTMENT · 7,615 people · 2019 | 2/5 | SYR4 |
| Di(2-ethylhexyl) Phthalate | 1.1 µg/L 18% of the EPA limit 6 µg/L Highest in the city: SCENIC VIEW ESTATES · 78 people · 2018 | 1/5 | SYR4 |
| Dibromoacetic Acid | 1.054 µg/L No EPA limit set Main supplier: DECORAH WATER DEPARTMENT · 7,615 people · 2019 | 1/5 | SYR4 |
| Arsenic | 1 µg/L 10% of the EPA limit 10 µg/L Highest in the city: DEERFIELD HEIGHTS ASSOCIATION · 28 people · 2019 | 1/5 | SYR4 |
| Lead | 0.0094 mg/L 63% of the EPA limit 0.0150 mg/L Main supplier: DECORAH WATER DEPARTMENT · 7,615 people · 2025 | 5/5 | LCR |
| PFBS | 0.0070 µg/L No EPA limit set Main supplier: DECORAH WATER DEPARTMENT · 7,615 people · 2023 | 1/5 | UCMR-5 |
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 Decorah
| Supplier | Population served |
|---|---|
| DECORAH WATER DEPARTMENT | 7,615 |
| FREEPORT WATER DISTRICT | 775 |
| SCENIC VIEW ESTATES | 78 |
| SHERMAN PLACE WATER & ROAD, INC. | 73 |
| DEERFIELD HEIGHTS ASSOCIATION | 28 |
Frequently asked questions about Decorah tap water
Is Decorah tap water safe to drink?
EPA testing detected 24 contaminants in the water serving Decorah. 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 Decorah?
5 public water suppliers report drinking-water monitoring for Decorah, Iowa to the EPA. Each is listed above with its population served.
What contaminants are in Decorah's water?
The contaminants EPA monitoring detected in Decorah include Nitrate, Fluoride, Copper, Barium, Total Haloacetic Acids (HAA5). 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.