What was found in Northbrook'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 | 987.4 µg/L 25% of the EPA limit 4000 µg/L Main supplier: NORTHBROOK · 34,407 people · 2019 | 2/6 | SYR4 |
| Nitrate | 432 µg/L 4.3% of the EPA limit 10000 µg/L Main supplier: NORTHBROOK · 34,407 people · 2019 | 1/6 | SYR4 |
| Nitrate-Nitrite | 393.95 µg/L 3.9% of the EPA limit 10000 µg/L Main supplier: NORTHBROOK · 34,407 people · 2016 | 1/6 | SYR4 |
| Copper | 244.7 µg/L 19% of the EPA limit 1300 µg/L Main supplier: NORTHBROOK · 34,407 people · 2017
Highest in the city: 373.3 µg/L — MISSION BROOK SD · 2,852 people · 2018 | 3/6 | SYR4 |
| TTHM | 43.26 µg/L 54% of the EPA limit 80 µg/L Main supplier: NORTHBROOK · 34,407 people · 2019 | 4/6 | SYR4 |
| Chloroform | 26.4 µg/L No EPA limit set Main supplier: NORTHBROOK · 34,407 people · 2019 | 4/6 | SYR4 |
| Total Haloacetic Acids (HAA5) | 20.85 µg/L 35% of the EPA limit 60 µg/L Main supplier: NORTHBROOK · 34,407 people · 2019
Highest in the city: 23.4 µg/L — MISSION BROOK SD · 2,852 people · 2019 | 4/6 | SYR4 |
| Barium | 22.09 µg/L 1.1% of the EPA limit 2000 µg/L Main supplier: NORTHBROOK · 34,407 people · 2019 | 2/6 | SYR4 |
| Lead | 13.475 µg/L 90% of the EPA limit 15 µg/L Main supplier: NORTHBROOK · 34,407 people · 2017
Highest in the city: 13.56 µg/L — SUNSET MHP · 1,400 people · 2019 | 3/6 | SYR4 |
| Dichloroacetic Acid | 11.78 µg/L No EPA limit set Main supplier: NORTHBROOK · 34,407 people · 2019
Highest in the city: 13.3 µg/L — MISSION BROOK SD · 2,852 people · 2019 | 4/6 | SYR4 |
| Bromodichloromethane | 11.51 µg/L No EPA limit set Main supplier: NORTHBROOK · 34,407 people · 2019
Highest in the city: 12.36 µg/L — SUNSET MHP · 1,400 people · 2019 | 3/6 | SYR4 |
| Trichloroacetic Acid | 8.519 µg/L No EPA limit set Main supplier: NORTHBROOK · 34,407 people · 2019
Highest in the city: 9.25 µg/L — MISSION BROOK SD · 2,852 people · 2019 | 4/6 | SYR4 |
| Dibromochloromethane | 6.628 µg/L No EPA limit set Main supplier: NORTHBROOK · 34,407 people · 2019
Highest in the city: 7.172 µg/L — SUNSET MHP · 1,400 people · 2019 | 3/6 | SYR4 |
| Monobromoacetic Acid | 2.842 µg/L No EPA limit set Main supplier: NORTHBROOK · 34,407 people · 2019 | 1/6 | SYR4 |
| Monochloroacetic Acid | 2.42 µg/L No EPA limit set Main supplier: NORTHBROOK · 34,407 people · 2019 | 1/6 | SYR4 |
| Bromoform | 0.6200 µg/L No EPA limit set Main supplier: NORTHBROOK · 34,407 people · 2019
Highest in the city: 2.282 µg/L — SUNSET MHP · 1,400 people · 2019 | 2/6 | SYR4 |
| Arsenic | 1.1 µg/L 11% of the EPA limit 10 µg/L Main supplier: NORTHBROOK · 34,407 people · 2019
Highest in the city: 2.206 µg/L — OASIS MHP · 3,000 people · 2019 | 2/6 | SYR4 |
| Selenium | 2 µg/L 4% of the EPA limit 50 µg/L Main supplier: NORTHBROOK · 34,407 people · 2019 | 1/6 | SYR4 |
| Combined Radium (-226 And -228) | 1.9875 pCi/L 40% of the EPA limit 5 pCi/L Highest in the city: OASIS MHP · 3,000 people · 2014 | 1/6 | SYR4 |
| Dibromoacetic Acid | 1.87 µg/L No EPA limit set Main supplier: NORTHBROOK · 34,407 people · 2019 | 3/6 | SYR4 |
| P-Dichlorobenzene | 0.8760 µg/L 1.2% of the EPA limit 75 µg/L Highest in the city: OASIS MHP · 3,000 people · 2019 | 1/6 | SYR4 |
| Heptachlor | 0.0540 µg/L 13% of the EPA limit 0.4000 µg/L Highest in the city: OASIS MHP · 3,000 people · 2018 | 1/6 | SYR4 |
| Lead | 0.0110 mg/L 73% of the EPA limit 0.0150 mg/L Main supplier: NORTHBROOK · 34,407 people · 2026 | 6/6 | 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 Northbrook
| Supplier | Population served |
|---|---|
| NORTHBROOK | 34,407 |
| OASIS MHP | 3,000 |
| MISSION BROOK SD | 2,852 |
| SUNSET MHP | 1,400 |
| HARBOR POINT ESTATES MHP | 1,064 |
| CAMBRIDGE COURTS MHP | 658 |
Frequently asked questions about Northbrook tap water
Is Northbrook tap water safe to drink?
EPA testing detected 23 contaminants in the water serving Northbrook. 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 Northbrook?
6 public water suppliers report drinking-water monitoring for Northbrook, Illinois to the EPA. Each is listed above with its population served.
What contaminants are in Northbrook's water?
The contaminants EPA monitoring detected in Northbrook include Fluoride, Nitrate, Nitrate-Nitrite, Copper, 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.