Water Quality in Naperville, IL: 6 Violations — Grade B
Grade B · Score 72/100 · 1 water system · Updated 2026-05-03
Naperville's water is mostly safe. Minor violations exist but are primarily monitoring-related.
Data: EPA Safe Drinking Water Information System (SDWIS) Last verified: 2026-05-03
SDWIS records for Naperville, IL show 6 EPA violations documented for the local water supply — these span the full range of reportable events from health-based exceedances to monitoring and reporting lapses registered with the federal program.
Water Quality Map: Naperville, IL
Each dot represents a ZIP code. Color indicates water quality grade. Tap a dot for details.
Water Quality by ZIP Code in Naperville
Water quality varies across Naperville's 6 ZIP codes. Check your specific ZIP for detailed contaminant data.
| ZIP Code | Grade | Score | Violations | Health | |
|---|---|---|---|---|---|
| 60540 | C | 67 | 1 | 0 | View report → |
| 60565 | C | 67 | 1 | 0 | View report → |
| 60563 | B | 72 | 1 | 0 | View report → |
| 60564 | B | 72 | 1 | 0 | View report → |
| 60567 | B | 75 | 1 | 0 | View report → |
| 60566 | B | 77 | 1 | 0 | View report → |
Water Quality Overview
Naperville, Illinois receives a water quality grade of B with an overall score of 72 out of 100, based on EPA compliance data from the Safe Drinking Water Information System (SDWIS).
The 1 water system serving Naperville have accumulated 6 EPA violations (all monitoring/reporting type). These violations are tracked across 6 ZIP codes serving approximately 156,406 people.
What Grade B Means
A grade of B indicates good compliance with EPA drinking water standards. While not perfect, Naperville's water systems meet the vast majority of federal requirements. Minor violations may exist but typically relate to monitoring or reporting rather than health-based standards.
Lead Levels
The average 90th percentile lead level across Naperville water systems is 0.0074 mg/L — within EPA limits. No ZIP codes exceed the EPA lead action level.
With 45% of homes built before 1986, Naperville has a higher-than-average risk of lead from older plumbing. Lead solder was banned in 1986, and homes built before this date may have lead in pipes, solder joints, or fixtures.
Radon Risk
Naperville is in EPA Radon Zone 2 (Moderate risk). Testing is recommended, especially for homes with basements or ground-level living spaces.
Water Systems Serving Naperville
Naperville is served by 1 community water system regulated under the Safe Drinking Water Act. These systems collectively serve approximately 156,406 people across 6 ZIP codes.
Each water system is identified by a Public Water System ID (PWSID) and is required to:
- Test for over 90 regulated contaminants on a regular schedule
- Report results to the EPA and state regulators
- Issue an annual Consumer Confidence Report (CCR) to all customers
- Take corrective action when violations occur
The EPA has taken 24 enforcement actions against water systems serving Naperville. Enforcement actions range from informal compliance assistance to formal orders and penalties.
How to Check Your Water in Naperville
Enter your ZIP code on ZipCheckup to see your specific water system data, including contaminant levels, violation history, and safety scores
Request your CCR — your water utility must provide an annual Consumer Confidence Report with detailed test results for all monitored contaminants
Get a home test — certified kits cost $20–$50 and test for lead, bacteria, and common contaminants. Professional lab tests ($150–$400) cover a broader panel
Consider filtration — NSF-certified filters can remove specific contaminants. Reverse osmosis removes the broadest range; activated carbon is effective for chlorine and many organics
Check for advisories — monitor your local utility website and local news for boil water advisories or system alerts
Contaminants Detected in Naperville Water Systems
The following contaminants have been detected or caused violations across Naperville's water systems:
| Contaminant | Category | MCL | Violations | ZIPs Affected | Health-Based |
|---|---|---|---|---|---|
| Total Trihalomethanes (TTHM) | Disinfection Byproducts | 0.08 mg/L | 6 | 6 | No |
MCL = Maximum Contaminant Level (EPA enforceable standard). Health-based violations indicate levels that may pose direct health risks.
EPA Enforcement History
The EPA and state regulators have taken 4 enforcement actions against water systems serving Naperville. Recent actions:
| Date | Action Type |
|---|---|
| 2024-06-06 | State Informal Action |
| 2023-09-08 | State Order Extension |
| 2023-07-11 | State Informal Action |
| 2023-07-11 | State Informal Enforcement |
Enforcement actions range from informal compliance assistance to formal orders and penalties. The most recent action was on 2024-06-06.
Naperville vs. Nearby Illinois Cities
How Naperville's water quality compares to similar cities in Illinois:
| City | Grade | Violations | Systems | Population |
|---|---|---|---|---|
| Naperville | B | 6 | 1 | 156,406 |
| Kankakee | D | 8 | 5 | 153,577 |
| Bondville | D | 0 | 1 | 150,000 |
| Elsah | C | 0 | 1 | 150,000 |
Recommended Water Filters for Naperville
Based on contaminants detected in Naperville's water supply, these filter types are recommended:
Granular Activated Carbon (GAC, whole-house POE)
- Removes: Trihalomethane (TTHM)
- Effectiveness: 80-99%
- Cost range: $400–$2000
- Certification: NSF/ANSI 53
- Recommended products:
Ion Exchange Water Softener (POE)
- Removes: Likely Source of ContaminationCombined Radium226/228
- Effectiveness: 90-97%
- Cost range: $500–$2500
- Certification: NSF/ANSI 44
- Recommended products:
- Waterdrop G3P800
- Fleck 5600SXT Softener
Water Quality by ZIP Code in Naperville
Water quality varies across Naperville's ZIP codes. The table below shows the worst-scoring and best-scoring areas:
| ZIP Code | Score | Grade | Violations | Health-Based |
|---|---|---|---|---|
| 60540 | 67 | C | 1 | 0 |
| 60565 | 67 | C | 1 | 0 |
| 60563 | 72 | B | 1 | 0 |
| 60564 | 72 | B | 1 | 0 |
| 60567 | 75 | B | 1 | 0 |
| 60566 | 77 | B | 1 | 0 |
Common Questions About Naperville Water
These are the most common questions residents search for about water quality in Naperville, Illinois:
Is Naperville water hard or soft? Water hardness varies by source. Naperville's 1 water system uses a single source. Check your ZIP code report for specific hardness data.
Can I drink Naperville tap water? Naperville's water receives a grade of B (72/100). No health-based violations have been recorded, but home testing is always recommended.
What is the best water filter for Naperville? Based on detected contaminants, a granular activated carbon (gac, whole-house poe) filter is most recommended. See our Water Filter Matcher for personalized recommendations.
Naperville vs. Illinois Average
Understanding how Naperville compares to the broader Illinois average helps contextualize your local water quality. Factors like water source, treatment methods, and infrastructure age all contribute to differences between cities in the same state.
To see how individual neighborhoods compare, check the ZIP code reports below — water quality can vary significantly even within Naperville.
ZIP Codes in Naperville
Naperville spans 6 ZIP codes. The ZIP with the lowest water quality score is 60540. Each ZIP code has its own water quality profile based on the specific water system serving that area. Check each ZIP code for detailed contaminant data, violation history, and system information.
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
- Enforcement: EPA ECHO database
- Filter recommendations: NSF/ANSI certified products
Updated daily.
Frequently Asked Questions
Your Water is Safe — Here's How to Keep It That Way
Grade B is excellent news. Here's what proactive homeowners do to maintain water quality:
Annual Water Testing
EPA recommends annual testing even with clean water. Home test kits: $20-$50. Catches changes before they become problems.
Maintenance Filtration
A basic carbon filter removes chlorine taste and catches emerging contaminants like PFAS that aren't yet fully regulated.
Plumbing Check
Even safe city water picks up lead from home pipes. If your home was built before 1986, a one-time pipe inspection is recommended.