Joliet, IL Water Quality
What's in Joliet's water?
Joliet had a health-based violation within the last five years. The required corrective action was reported, but it happened recently enough to matter. 160,000 people get their water from it, across 49,000 connections.
Joliet's record against the rest of the country
64 total violations and 42 health-based ones put Joliet at the 97th percentile nationally for violation burden, rank 351 of 12,903.
How Joliet compares within IL
Joliet's 42 health-based violations sit above the IL average of 5.1, across 572 systems statewide. The filter guide explains what a violation like this actually calls for.
Most recent violation on record
The last violation EPA has on record for Joliet is from 2025-05-10 (health-based: 2025-05-10). Last reported to EPA: 05/27/2026.
What kind of problem, specifically
Joliet's flagged contaminants and rule violations, grouped by what they actually mean for a filter choice rather than left as EPA's raw code list:
- Lead & copper - flagged from: Lead and Copper Rule Revisions; Lead and Copper Rule
- Microbial contamination / treatment technique - flagged from: Coliform (TCR)
- Radionuclides - flagged from: Combined Radium (-226 and -228); Gross Alpha, Excl. Radon and U
The most severe category on record is lead & copper, which points toward a lead-class filter if you want to address it directly.
What this data is and is not
This is what Joliet reported to its state primacy agency and EPA under the Safe Drinking Water Act - real regulatory record, not a lab test of your specific tap. Water quality can still change between the meter and the faucet - household plumbing sits outside what a record of 64 logged violations can see. The guide to what this data misses covers that gap.