Naperville, IL Water Quality
Naperville, IL has 1 public water system serving 156,406 people. The average Water Safety Score is 88/100 (B). No health violations are on record.
Water Systems in Naperville
Contaminants Detected in Naperville Water
| Contaminant | Systems Detected | Exceeding MCL |
|---|---|---|
| Haloacetic Acids (HAA5) | 1 | 0 |
Frequently Asked Questions
Naperville has 1 public water system serving 156,406 people. The average Water Safety Score is 88/100. No health violations are currently on record. Check individual systems below for details.
Naperville water systems have detected 1 contaminant, including Haloacetic Acids (HAA5). No contaminant exceedances above EPA limits are currently recorded.
The Water Safety Score (0-100, grades A through F) weighs health-based violations (40%), contaminant exceedances (30%), enforcement history (20%), and monitoring violations (10%). Scores are based on EPA SDWIS data from the last 10 years.
Request your utility's Consumer Confidence Report (CCR), consider an independent water test from a certified lab, and look into NSF-certified water filters for specific contaminants of concern. For lead, run cold water for 30 seconds before drinking.
Water quality data sourced from EPA's Safe Drinking Water Information System. City data aggregates all public water systems serving the municipality.
The this entity record above pulls directly from the EPA Safe Drinking Water Information System (SDWIS). What follows is the per-entity context — how this entity sits in the broader U.S. public drinking-water safety distribution and which underlying factors drive the headline numbers.
The methodology behind every numeric value on this page is publicly documented on the the EPA Safe Drinking Water Information System (SDWIS) portal and described in detail on this site’s methodology page. Refresh cadence varies by underlying series; the page surfaces the as-of date for each number so readers can trace any figure back to the source release.
For readers using this page as a decision input, the related-entity pages elsewhere on the site provide the comparison set. The most useful comparison for this entity is typically a peer within U.S. public water systems with similar size, similar exposure, or similar geography — not the national-level summary alone.
Source: EPA Ground Water and Drinking Water, 2026.