Naperville, IL: 6 Violations — 72/100 (2026)
6 ZIP codes · 8 water systems · Updated 2026-06-03
Water utilities in Naperville have maintained a consistent compliance record over recent monitoring periods — the city's above-average grade in IL reflects low violation rates and no systemic health concerns flagged in current data.
How Naperville Compares
Data: EPA SDWIS Last verified: 2026-06-03
Water Quality Map: Naperville, IL
Each dot represents a ZIP code. Color indicates water quality grade. Tap a dot for details.
Score Distribution
How ZIP codes in Naperville score across all safety grades.
What You Should Know About Naperville Water
- Your city's water systems recorded 6 violations in the past 5 years.
- Average lead level: 0.0074 mg/L.
- Homes built before 1986: 45% — older plumbing may contain lead solder.
- Estimated remediation: $1,483 per household.
- CDC health risk index: 10.67.
Who Supplies Your Water in Naperville
Federal records list 8 water systems tied to Naperville, IL. Of those, 3 are the primary providers, meaning service conditions, rate structures, and compliance histories can differ depending on where a property sits.
Overview
We track water quality and home safety data for 6 ZIP codes in Naperville, Illinois (population ~167,976), covering 8 community water systems serving approximately 587,503 people region-wide.
6 of 6 ZIP codes (100%) have recorded EPA violations. All violations are monitoring/reporting type.
Home Safety Score
Average Home Safety Score for Naperville: B (72/100)
The score combines three factors:
| Factor | What It Measures |
|---|---|
| Water Quality | EPA violations and compliance history |
| Lead Levels | 90th percentile lead concentration vs EPA action level |
| Radon Risk | EPA radon zone classification |
Water Sources
Naperville water systems draw from: Surface water.
Lead & Copper
- Average lead level (90th percentile): 0.0074 mg/L (EPA action level: 0.015 mg/L)
- 0 ZIP codes exceed the EPA lead action level
Radon Risk
Dominant radon zone: Zone 2 (Moderate Risk)
- Zone 1 (High): 0 ZIP codes
- Zone 2 (Moderate): 6 ZIP codes
- Zone 3 (Low): 0 ZIP codes
The EPA recommends testing homes in Zone 1 and Zone 2 areas for radon.
Top Contaminants
| Contaminant | Category | Violations | ZIPs Affected |
|---|---|---|---|
| Total Trihalomethanes (TTHM) | Disinfection Byproducts | 7 | 6 |
Areas with Most Violations
| ZIP Code | Safety Score | Violations | Health-Based | System |
|---|---|---|---|---|
| 60540 | C | 1 | 0 | Naperville |
| 60563 | B | 1 | 0 | Naperville |
| 60564 | B | 1 | 0 | Naperville |
| 60565 | C | 1 | 0 | Naperville |
| 60566 | B | 1 | 0 | Naperville |
| 60567 | B | 1 | 0 | Naperville |
All ZIP Codes in Naperville
- 60540 [C] — 1 violation
- 60563 [B] — 1 violation
- 60564 [B] — 1 violation
- 60565 [C] — 1 violation
- 60566 [B] — 1 violation
- 60567 [B] — 1 violation
Data Sources
- Water quality: EPA Safe Drinking Water Information System (SDWIS)
- Lead/copper: EPA Lead and Copper Rule sampling data
- Radon: EPA Map of Radon Zones
Updated daily.
Health Outcomes in Naperville
Source: CDC PLACES (County-level estimates). Water contamination can correlate with respiratory and chronic health conditions.
Compared to National Average
Vertical line = national average. ■ Above national · ■ Below national
Top Contaminants in Naperville Water
Based on EPA violation records. Check your ZIP code report for system-specific contaminant data.
Housing & Infrastructure in Naperville
With 45% of homes built before 1986, lead solder in plumbing is a potential concern. The EPA banned lead solder in 1986, but many older homes retain original plumbing.
Source: U.S. Census Bureau American Community Survey (ACS).
Housing Age Profile
Because Naperville's housing stock spans a wide range of construction eras, the median build year of 1987 lands in a zone where two distinct risk populations share the same residential market. Homes built before 1986 may have lead-soldered copper plumbing joints — that practice was federally prohibited in 1986 but remained standard until then. The fraction built before 1970 face an additional risk: lead pipes used for service line connections were common before that decade, meaning both the pipe and the solder may be lead-containing in the oldest structures. Residents in mid-century or earlier homes face a different risk environment than neighbors in houses built after 1986, even if they drink from the same utility's supply — and that property-level divergence is what makes the age distribution above more diagnostic than the city-wide median alone.
Most homes in Naperville were built after 1986, reducing the risk of lead contamination from plumbing. Older homes should still be tested.
Source: U.S. Census Bureau ACS B25034.
Cost Context: What Remediation Means for Naperville Homeowners
While no remediation project is entirely without cost, the relationship between estimated remediation and property values in Naperville is notably favorable — the equity share is small enough that the household financial perspective is one of proportionality rather than pressure, and most homeowners can treat it as routine planning rather than a significant financial event.
Remediation costs in Naperville are relatively low compared to home values. The $717–$2,433 estimated range is a small fraction of median property value. Home values are 174% above the Illinois average.
Lead Exposure Risk for Children in Naperville
Why children are most at risk: The CDC states there is no safe level of lead exposure for children. Children under 6 absorb lead more readily than adults, and even low levels can cause developmental delays, learning difficulties, and behavioral problems.
In recent monitoring under the Lead and Copper Rule, citywide samples for Naperville have approached or crossed the regulatory action level on multiple occasions. Combined with 45% of stock dating from the pre-rule era, the picture supports baseline single-tap reads as a standard household-level step.
Sources: EPA Lead and Copper Rule, U.S. Census Bureau ACS, CDC childhood lead poisoning prevention guidelines.
Flood & Climate Risk in Naperville
Across the NFIP's long tracking period, Naperville shows 225 claims and 83% of ZIP codes within FEMA-designated flood zones — figures that place it in moderate flood exposure territory. At this level, the water-quality implications of flooding — contaminated wells, stressed treatment intake, distribution backflow — move from theoretical edge cases to genuine periodic risks, particularly during higher-severity events.
Naperville has a moderate flood history with 225 FEMA claims averaging $4,600 per payout. 83% of ZIP codes fall within FEMA flood zones. Flood events can contaminate drinking water and overwhelm treatment systems.
How flooding affects water quality: Flood events can introduce sewage, agricultural runoff, and industrial chemicals into water supplies. Even after floodwaters recede, contamination can persist in wells and aging infrastructure. Flood damage can add significantly to the estimated <strong>$1,483</strong> remediation cost per household.
Residents in flood-prone areas should consider flood insurance even outside FEMA zones — over 25% of flood claims come from low-to-moderate risk areas. After any flood event, test your water before drinking.
Source: FEMA National Flood Insurance Program (NFIP) claims data, FEMA flood zone designations.
Deep Dive Reports
Detailed analysis for Naperville, IL