Drinking water quality · 2025
What's in Northbrook, IL tap water
1 contaminants were measured in the Northbrook, IL water system's 2025 annual report. Each is shown below against its federal limit — 1 sit at or above that limit.
- Reporting year
- 2025
- Contaminants measured
- 1
- Over federal limit
- 1
- Approaching the limit
- 0
- Worst contaminant
- Lead
- Service area
- IL
Compliance history
Federal Safe Drinking Water Act violation & enforcement records (EPA SDWIS). A violation is a regulatory determination by the state or EPA — separate from the measured levels above.
- Treatment technique violationHealth-based1 violation on record · most recent Jan 1993resolved
Source: EPA SDWIS / ECHO. View the full federal record on EPA ECHO ↗
Metals
| Contaminant | Measured | Federal limit | Status |
|---|---|---|---|
| LeadA toxic metal that leaches into water from old service lines, solder, and plumbing fixtures. | 0.016 mg/L90th percentileAt the tap | 0.015 mg/LAction level | At or above the limit |
People also ask about Northbrook, IL's water
+Is Northbrook, IL tap water safe to drink in 2025?
The 2025 Consumer Confidence Report for the Northbrook, IL water utility lists 1 contaminant at or above the federal limit: Lead. Whether that means the water is "unsafe" depends on which contaminant, how long the exposure, and individual health factors. The table on this page shows the measured value, the federal threshold, and the regulated statistic used for compliance.
+What contaminants are in Northbrook, IL tap water?
1 contaminants were measured in Northbrook, IL's 2025 Consumer Confidence Report, spanning metals. 1 have an enforceable federal limit; the rest are detected but unregulated. Every measured value, in the utility's own units, is on this page.
+Which contaminants exceed federal limits in Northbrook, IL tap water?
One contaminant in Northbrook, IL's 2025 report sits at or above the federal limit: Lead (1.1× the limit). The EPA enforces these limits against the regulated reporting statistic — typically a running annual average or 90th percentile — not a one-off sample spike.
+What is the worst contaminant in Northbrook, IL tap water?
The contaminant with the highest measured value relative to its federal limit in the 2025 report is Lead, at 1.1× the federal threshold. It belongs to the metals family of contaminants.
+Where does the data on this page come from?
Every value is transcribed from Northbrook, IL's 2025 Consumer Confidence Report — the annual drinking-water report every U.S. public water utility is required by federal law to publish. The original source document is archived and viewable on this site. A water-quality report covers an entire service area, not a single address.
+How often is Northbrook, IL's water quality data updated?
Each U.S. public water utility publishes one Consumer Confidence Report per year, covering the prior calendar year's measurements. This page reflects the 2025 report; a new report will replace it once the utility publishes its next annual update.