What was found in Delafield'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 | 2500 µg/L 25% of the EPA limit 10000 µg/L Main supplier: DELAFIELD SQUARE · 587 people · 2018 | 6/17 | SYR4 |
| Nitrate | 1500 µg/L 15% of the EPA limit 10000 µg/L Highest in the city: NASHOTAH HOUSE · 350 people · 2017 | 6/17 | SYR4 |
| Fluoride | 269 µg/L 6.7% of the EPA limit 4000 µg/L Main supplier: DELAFIELD SQUARE · 587 people · 2018
Highest in the city: 882.25 µg/L — APARTMENTS OF STONERIDGE · 75 people · 2018 | 16/17 | SYR4 |
| Barium | 1.5665 µg/L 0.1% of the EPA limit 2000 µg/L Main supplier: DELAFIELD SQUARE · 587 people · 2018
Highest in the city: 601 µg/L — CAMBRIDGE PLACE OF DELAFIELD · 50 people · 2018 | 15/17 | SYR4 |
| Copper | 150 µg/L 12% of the EPA limit 1300 µg/L Main supplier: DELAFIELD SQUARE · 587 people · 2019
Highest in the city: 589 µg/L — ST JOHNS NORTHWESTERN ACADEMIES · 340 people · 2019 | 17/17 | SYR4 |
| Toluene | 477.24 µg/L 48% of the EPA limit 1000 µg/L Highest in the city: DELAFIELD WOODS 828 · 40 people · 2018 | 4/17 | SYR4 |
| Nitrite | 135 µg/L 14% of the EPA limit 1000 µg/L Highest in the city: ST JOHNS NORTHWESTERN ACADEMIES · 340 people · 2018 | 2/17 | SYR4 |
| Gross Alpha, Excl. Radon And U | 24.62 pCi/L 164% of the EPA limit, at the 95th percentile of samples — 15 pCi/L Highest in the city: CAMBRIDGE PLACE OF DELAFIELD · 50 people · 2019 | 14/17 | SYR4 |
| Lead | 4.54 µg/L 30% of the EPA limit 15 µg/L Main supplier: DELAFIELD SQUARE · 587 people · 2019
Highest in the city: 18.76 µg/L — ST JOHNS NORTHWESTERN ACADEMIES · 340 people · 2019 | 16/17 | SYR4 |
| Combined Radium (-226 And -228) | 1.4 pCi/L 28% of the EPA limit 5 pCi/L Main supplier: DELAFIELD SQUARE · 587 people · 2015
Highest in the city: 9.85625 pCi/L — CAMBRIDGE PLACE OF DELAFIELD · 50 people · 2019 | 16/17 | SYR4 |
| Arsenic | 3.22 µg/L 32% of the EPA limit 10 µg/L Main supplier: DELAFIELD SQUARE · 587 people · 2018
Highest in the city: 6.6 µg/L — SANCTUARY OF DELAFIELD · 27 people · 2018 | 10/17 | SYR4 |
| Total Haloacetic Acids (HAA5) | 5.913 µg/L 9.9% of the EPA limit 60 µg/L Highest in the city: ST JOHNS NORTHWESTERN ACADEMIES · 340 people · 2019 | 4/17 | SYR4 |
| Gross Beta Particle Activity | 4.97 pCi/L No EPA limit set Highest in the city: APARTMENTS OF STONERIDGE · 75 people · 2015 | 1/17 | SYR4 |
| TTHM | 4.548 µg/L 5.7% of the EPA limit 80 µg/L Highest in the city: ST JOHNS NORTHWESTERN ACADEMIES · 340 people · 2019 | 4/17 | SYR4 |
| Di(2-ethylhexyl) Phthalate | 4.1 µg/L 68% of the EPA limit 6 µg/L Highest in the city: KNOLLCREST · 66 people · 2018 | 2/17 | SYR4 |
| Chloroform | 3.44 µg/L No EPA limit set Highest in the city: ST JOHNS NORTHWESTERN ACADEMIES · 340 people · 2019 | 1/17 | SYR4 |
| Chromium | 2.9675 µg/L 3% of the EPA limit 100 µg/L Highest in the city: NASHOTAH HOUSE · 350 people · 2018 | 3/17 | SYR4 |
| Dichloroacetic Acid | 2.84 µg/L No EPA limit set Highest in the city: ST JOHNS NORTHWESTERN ACADEMIES · 340 people · 2019 | 3/17 | SYR4 |
| Trichloroacetic Acid | 2.565 µg/L No EPA limit set Highest in the city: ST JOHNS NORTHWESTERN ACADEMIES · 340 people · 2019 | 3/17 | SYR4 |
| Bromodichloromethane | 1.76 µg/L No EPA limit set Highest in the city: ST JOHNS NORTHWESTERN ACADEMIES · 340 people · 2019 | 2/17 | SYR4 |
| Dibromochloromethane | 1.11 µg/L No EPA limit set Highest in the city: ST JOHNS NORTHWESTERN ACADEMIES · 340 people · 2019 | 1/17 | SYR4 |
| Antimony, Total | 1.1 µg/L 18% of the EPA limit 6 µg/L Highest in the city: SANCTUARY OF DELAFIELD · 27 people · 2018 | 1/17 | SYR4 |
| Dibromoacetic Acid | 0.5515 µg/L No EPA limit set Highest in the city: ST JOHNS NORTHWESTERN ACADEMIES · 340 people · 2019 | 3/17 | SYR4 |
| Combined Uranium | 0.4042 µg/L 1.3% of the EPA limit 30 µg/L Highest in the city: DELAFIELD WATERWORKS · 300 people · 2014 | 4/17 | SYR4 |
| Styrene | 0.3300 µg/L 0.3% of the EPA limit 100 µg/L Highest in the city: NASHOTAH HOUSE · 350 people · 2018 | 1/17 | SYR4 |
| Cadmium | 0.2600 µg/L 5.2% of the EPA limit 5 µg/L Highest in the city: ST JOHNS NORTHWESTERN ACADEMIES · 340 people · 2018 | 1/17 | SYR4 |
| Monobromoacetic Acid | 0.2500 µg/L No EPA limit set Highest in the city: WELLS ST STATION 425 WEST · 25 people · 2019 | 1/17 | SYR4 |
| Bromoform | 0.2000 µg/L No EPA limit set Highest in the city: ST JOHNS NORTHWESTERN ACADEMIES · 340 people · 2019 | 1/17 | SYR4 |
| Lead | 0.0012 mg/L 8% of the EPA limit 0.0150 mg/L Main supplier: DELAFIELD SQUARE · 587 people · 2025
Highest in the city: 0.0136 mg/L — KNOLLCREST · 66 people · 2023 | 17/17 | 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 Delafield
| Supplier | Population served |
|---|---|
| DELAFIELD SQUARE | 587 |
| NASHOTAH HOUSE | 350 |
| ST JOHNS NORTHWESTERN ACADEMIES | 340 |
| DELAFIELD WATERWORKS | 300 |
| ARBORS | 280 |
| LAKE COUNTRY APARTMENTS | 84 |
| APARTMENTS OF STONERIDGE | 75 |
| KNOLLCREST | 66 |
| CAMBRIDGE PLACE OF DELAFIELD | 50 |
| DELAFIELD WOODS 828 | 40 |
| DELAFIELD LAKES 402 | 40 |
| DELAFIELD LAKES 404 | 40 |
| DELAFIELD WOODS 411 | 40 |
| QUAIL HOLLOW CONDOS | 30 |
| SANCTUARY OF DELAFIELD | 27 |
| WELLS ST STATION 425 WEST | 25 |
| WELLS ST STATION 435 EAST | 25 |
Frequently asked questions about Delafield tap water
Is Delafield tap water safe to drink?
EPA testing detected 29 contaminants in the water serving Delafield. 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 Delafield?
17 public water suppliers report drinking-water monitoring for Delafield, Wisconsin to the EPA. Each is listed above with its population served.
What contaminants are in Delafield's water?
The contaminants EPA monitoring detected in Delafield include Nitrate-Nitrite, Nitrate, Fluoride, Barium, 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.