NORTHBROOK vs CHICAGO
Water quality comparison — risk levels, violations, PFAS records, and contaminants
Quick Answer
CHICAGO has a lower risk classification (safe). NORTHBROOK has 0 open health-based violations and 116 PFAS records. CHICAGO has 0 open health-based violations and 232 PFAS records.
Illinois · IL0312070
Low Concern
Minor detections below regulatory limits. Routine monitoring adequate.
0
Open violations
116
PFAS records
Illinois · IL0316000
No Concerns Detected
Water meets all safety standards with no detected exceedances.
0
Open violations
232
PFAS records
Head-to-Head Comparison
| Metric | NORTHBROOK | CHICAGO |
|---|---|---|
| State | Illinois | Illinois |
| Risk Level | Low Concern | No Concerns Detected |
| Population Served | 34,407 | 2,746,388 |
| Open Health Violations | 0 | 0 |
| Total Violations | 9 | 50 |
| PFAS Records | 116 | 232 |
| Ownership | Local | Local |
| Service Type | Surface water | Surface water |
| City Served | Northbrook | Chicago |
Contaminants in Violation Records
NORTHBROOK
- Lead
- Total Trihalomethanes (TTHMs)
CHICAGO
- Lead
- Nitrate
- Turbidity
Key Differences
NORTHBROOK has a low risk rating vs. safe for CHICAGO.
NORTHBROOK has 116 PFAS records vs. 232 for CHICAGO.
What Should I Do?
If either utility shows open violations or elevated PFAS records, consider:
- Installing a reverse osmosis filter — removes PFAS, lead, arsenic, nitrates, and most heavy metals.
- Requesting your utility’s annual Consumer Confidence Report (CCR) for the most current test results.
- Ordering a certified lab water test if you want contaminant-specific data for your address.
Frequently Asked Questions
Which is safer — NORTHBROOK or CHICAGO?
CHICAGO has a lower risk classification (safe). CHICAGO has 0 open health-based violations compared to 0 for the other system.
What does "open health-based violation" mean?
An open health-based violation means a water system has exceeded an EPA Maximum Contaminant Level (MCL) or failed to meet a treatment technique — and the violation has not yet been resolved. These are the most serious type of water quality violations.
How current is this data?
Violation data comes from EPA's Safe Drinking Water Information System (SDWIS), which is updated as utilities report. PFAS data comes from EPA's UCMR 5 monitoring (2023–2025). Risk levels are recalculated daily.
What does PWSID mean?
PWSID stands for Public Water System ID — a unique federal identifier assigned to each community water system. You can use it to look up a system in EPA's ECHO database.