Naperville
EPA ID: IL0434670 · 156,406 people served · 16 ZIP codes
EPA records: Naperville, 1 past violation, all resolved, 156,406 served.
Data: EPA SDWIS Last verified: 2026-04-02
Compliance Trajectory
Stable · Risk tier: High · 95% chance of violation in next 12 months
Violations went from 1 (2021) to 2 (2025). Violation counts have remained relatively steady.
Service Area Map
Coverage area for Naperville Source: EPA SDWIS service area boundaries.
Service area boundary — Grade B
Service Area Demographics
The Naperville serves a community with a median household income of $115,547 and an estimated 465,123 residents across its service area. Approximately 45% of housing stock was built before 1986, which increases the likelihood of lead service lines and older plumbing.
🌊 Where Does Your Water Come From?
Naperville's water is drawn from rivers, lakes, or reservoirs. Surface water sources are more exposed to agricultural runoff, stormwater, and upstream discharges, but they typically receive more intensive treatment before reaching your tap.
About 1% of homes in DuPage County, Illinois rely on private wells rather than public water systems. Private well owners are responsible for their own water testing and treatment.
Wastewater Proximity Note: This service area ranks in the 70th percentile nationally for proximity to wastewater discharge points. Surface water sources near wastewater outfalls may face additional treatment challenges.
Superfund Proximity Note: This service area ranks in the 65th percentile nationally for proximity to Superfund (NPL) sites.
Infrastructure Risk
Detected Contaminants
How Naperville compares to EPA limits
What This Means For You
Total Trihalomethanes (TTHM) at 1 mg/L exceeds the EPA maximum of 0.08 mg/L. Bladder & rectal cancer risk; reproductive concerns. Consider granular activated carbon (GAC) filtration.
PFAS Detected in Service Area
PFAS ("forever chemicals") have been detected in water serving this system's area. 15 detections recorded.
Total Trihalomethanes (TTHM) was detected in this water system. granular activated carbon (GAC) filtration can reduce exposure.
Find a certified water filter →Comparable Water Systems
Similar-sized systems in Illinois
Estimated Remediation Costs
Average estimated costs across ZIP codes served by this system
Based on national averages for common remediation projects. Actual costs vary by property. Only issues flagged by EPA, FEMA, or state data for each ZIP code are included.
System Overview
Naperville (EPA ID: IL0434670) is a community water system in Illinois that serves approximately 156,406 people from surface water sources.
This system provides water to 16 ZIP codes across 9 communities.
Average Home Safety Score: B (72/100)
Based on water quality violations, lead levels, and radon risk across all ZIP codes served by this system.
Violation History
Recent Violations
| Date | Contaminant | Type | Status |
|---|---|---|---|
| April 1, 2023 | Total Trihalomethanes (TTHM) | Monitoring | Resolved |
Contaminants Detected
The following contaminants have been flagged in EPA records for this water system:
| Contaminant | Category | Violations | Health-Based |
|---|---|---|---|
| Total Trihalomethanes (TTHM) | Disinfection Byproducts | 1 | No |
Lead & Copper
EPA Lead and Copper Rule sampling data for ZIP codes served by this system:
| ZIP Code | Lead Level | Exceeds Limit | Sample Date |
|---|---|---|---|
| 60540 | 0.0074 mg/L | No | N/A |
| 60563 | 0.0074 mg/L | No | N/A |
| 60564 | 0.0074 mg/L | No | N/A |
| 60565 | 0.0074 mg/L | No | N/A |
| 60566 | 0.0074 mg/L | No | N/A |
| 60567 | 0.0074 mg/L | No | N/A |
Radon Risk in Service Area
Dominant radon zone for ZIP codes served by this system: Zone 2 (Moderate Risk)
The EPA recommends testing homes in Zone 1 and Zone 2 areas for radon.
Need help with your water quality?
Typical cost: Water test: typically $20–$50 (DIY kit) · Professional inspection: $150–$400
Find the Right Water FilterFree tip: Let cold water run for 2 minutes before drinking — this helps flush lead from your pipes.
ZIP Codes Served
Coverage: 14 ZIP codes confirmed via EPA Community Water System Service Area Boundaries v3 plus 2 additional ZIPs inferred from SDWIS registry data. The EPA-confirmed set is the most reliable; SDWIS-inferred entries may be narrower than the real deployment area.
- 60185 — West Chicago
- 60189 — Wheaton
- 60440 — Bolingbrook
- 60502 — Aurora
- 60503 — Aurora
- 60504 — Aurora
- 60517 — Woodridge
- 60532 — Lisle
- 60540 — Naperville
- 60555 — Warrenville
- 60563 — Naperville
- 60564 — Naperville
- 60565 — Naperville
- 60566 — Naperville
- 60567 — Naperville
- 60585 — Plainfield
Data Sources
This report uses public data from the EPA Safe Drinking Water Information System (SDWIS). View the full compliance record for Naperville (IL0434670) on EPA.gov.
Frequently Asked Questions
Is Naperville water safe to drink?
Naperville has only monitoring/reporting violations, which are procedural in nature. The system meets federal health-based standards.
How many people does Naperville serve?
Naperville serves approximately 156,406 people across 16 ZIP codes in Illinois.
Where does Naperville get its water?
The primary water source is surface water.
Contact Your Water Utility
Public-record contact information for the water utility serving this system. Use these channels to request water quality reports, ask about service, or report issues directly.
Contact information from City of Naperville Water Utility Consumer Confidence Report.
ZipCheckup is not affiliated with this water utility, does not act as its agent, and does not provide customer support for it. Contact details shown are public-record information from CCR filings. For service issues, contact the utility directly using the information above.
Federal UCMR5 PFAS Monitoring: Tested Clean
This water system was tested under the federal EPA Unregulated Contaminant Monitoring Rule (UCMR5). No PFAS compounds were detected.
Current MCL reflects the lowest state-enforceable limit (NYS 10 ppt for PFOA/PFOS, effective August 2020). The federal final MCL of 4 ppt for PFOA/PFOS (EPA April 2024 rule) is not enforceable until April 2029. Detections above 4 ppt but below 10 ppt are below current MCL but above the future federal limit.
Source: U.S. EPA UCMR5 (Unregulated Contaminant Monitoring Rule, 5th cycle) — per-system federal sampling, 2023–2025. EPA UCMR5 monitoring program →
Lead Service Line Inventory
Service line breakdown reported under the federal Lead and Copper Rule Improvements (LCRI) inventory requirement:
Federal LCRI rule (effective October 2024) requires every public water system to inventory its service lines and complete lead-line replacement within 10 years.
Source: EPA SDWIS Federal Service Line Inventory (Phase 2) · Submitted 2026
ZipCheckup is not affiliated with the utility or state agency. Inventory figures render verbatim from the public LCRI submission cited above; ZipCheckup does not perform inspections or replacements.
How Water Systems Appear in Rankings
Water systems are evaluated by violation history, contaminant detections, and service population. Larger systems with more service connections appear in more rankings.
- #20 / 50 Highest Exposure Burden (Illinois)
Frequently Asked Questions
What You Can Do
Test your water
Home test kits can detect lead, bacteria, and other contaminants at your tap. Find the right filter →
Check your specific ZIP code
Water quality can vary within a system. View nearest ZIP report →
Contact your utility
Naperville (EPA ID: IL0434670) — request the latest Consumer Confidence Report or ask about specific contaminants.