MARK vs CHICAGO
Water quality comparison — risk levels, violations, PFAS records, and contaminants
Quick Answer
Both utilities share the same risk level (safe). MARK has 0 open health-based violations and 0 PFAS records. CHICAGO has 0 open health-based violations and 232 PFAS records.
Illinois · IL1550250
No Concerns Detected
Water meets all safety standards with no detected exceedances.
0
Open violations
0
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
Contaminants in Violation Records
MARK
No named contaminants in violation records.
CHICAGO
- Lead
- Nitrate
- Turbidity
Key Differences
MARK has 0 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 — MARK or CHICAGO?
Both utilities share the same risk level (safe). Both utilities have similar violation profiles — review the full data above to decide based on specific contaminants that concern you.
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.