Is Naperville, IL tap water safe?
Supplied by Naperville Water System · serves 156,406 people (45,580 connections) · Purchased surface water · EPA ID IL0434670
Data: U.S. EPA · How we read the data · How we check it
Buys water from Du Page Water Commission. Treated water bought from another system can carry that system's contaminants.
Summary
No federal limits exceeded in EPA data.
- PFAS
- Not detectedNone of 29 PFAS found above EPA's reporting limits in 4 samples (2023–2025).
- Lead
- Below action level6.1 ppb (parts per billion) at the 90th percentile: 9 in 10 homes sampled were at or below it. Action level 15 ppb, falling to 10 ppb in Nov 2027. Monitoring period Jan 2026 – now, still in progress (results reported so far). Your home's pipes can make yours higher.
- Violations
- None health-basedNo health-based violations since 2016.
- Built before 1986, or not sure what your service line is made of? Check your service line and test your tap. Utility data can't show your pipes.
- Tested your own tap? Compare your result with these numbers. Moving? Compare this system with another.
- Read Naperville Water System's annual water quality report (Consumer Confidence Report). It lists every regulated contaminant tested and is usually on the utility's website or mailed with your bill, and you can also request it at (630) 420-6125. EPA: how to find it.
PFAS (“forever chemicals”)
EPA UCMR 5: 1 entry point tested Jan 2024 to Oct 2024. "Average" is the highest entry-point average (non-detects counted as zero), the way EPA compares UCMR 5 results to the limits. ppt = parts per trillion. These results do not determine compliance.
| Contaminant | Highest average |
|---|---|
| PFOA Not detected Limit 4 ppt | – |
| PFOS Not detected Limit 4 ppt | – |
| PFHxS Not detected Limit 10 ppt | – |
| PFNA Not detected Limit 10 ppt | – |
| HFPO-DA (GenX) Not detected Limit 10 ppt | – |
| Hazard Index (a combined score for PFHxS, PFNA, GenX and PFBS, where above 1 is over the limit) Not detected Limit 1 | – |
| PFBS Not detected Guideline 2,000 ppt | – |
| PFBA Not detected Guideline 6,000 ppt | – |
| PFHxA Not detected Guideline 3,000 ppt | – |
29 PFAS tested, 0 detected at least once. "Not detected" means below EPA's reporting limit (about 2 to 20 ppt depending on the chemical), not proven zero. PFAS not listed were not detected. The limits for PFHxS, PFNA, GenX and the Hazard Index were proposed for rescission in May 2026. That proposal is not final. Systems have until 2029 to meet the limits.
Lithium
Not detected in 4 samples (reporting limit 9 ppb). About lithium.
Lead and copper
Latest 90th percentile: 6.1 ppb lead (Jan 2026 – now (in progress)). Below action level
Highest since 2016: 7.1 ppb (Dec 2025).
| Monitoring period | Lead (90th pct.) |
|---|---|
| Jan 2026 – now (in progress) | 6.1 ppb |
| Jul 2025 – Dec 2025 | 7.1 ppb |
| Jan 2025 – Dec 2025 | 0 ppb |
Earlier results (9)
| Jan 2025 – Jun 2025 | 4.7 ppb |
| Jan 2024 – Dec 2024 | 4.2 ppb |
| Jan 2023 – Dec 2023 | 5.06 ppb |
| Jan 2022 – Dec 2022 | 0 ppb |
| Jan 2019 – Dec 2021 | 5.14 ppb |
| Jan 2016 – Dec 2018 | 0 ppb |
| Jan 2013 – Dec 2015 | 0 ppb |
| Jan 2010 – Dec 2012 | 0 ppb |
| Jan 2008 – Dec 2010 | 0 ppb |
Lead comes from pipes and fixtures, not the source water, so it varies home to home. The 90th percentile means 9 in 10 sampled homes were at or below it. More on lead.
Violations
Health-based violations mean a contaminant exceeded a limit or a required treatment step was missed. Monitoring and reporting violations mean required tests or reports were late or missing, so the water's quality during that time is unknown. The total includes every violation in EPA's records, most of them paperwork.
Earlier EPA testing (2013–2020)
| Contaminant | Highest | Guideline |
|---|---|---|
| Chromium-6 | 0.23 ppb | – |
| Molybdenum | 1.1 ppb | 40 ppb |
| Strontium | 0.13 ppm | 1.5 ppm |
| Vanadium | 0.39 ppb | 21 ppb |
| Chlorate | 30 ppb | 210 ppb |
Where it serves
Naperville
ZIP codes the system reported serving: 60540, 60563, 60564, 60565, 60566, 60567
Nearby utilities
- Illinois American Water – West Suburban Bolingbrook · 5 mi
- Aurora Water System Aurora · 7 mi
- Wheaton Water System Wheaton · 8 mi
- Romeoville Water System Romeoville · 9 mi
- Plainfield Water System Plainfield · 9 mi
- Crest Hill Water System Crest Hill · 12 mi · PFAS above limit
Questions
Is Naperville tap water safe to drink?
Most of Naperville gets its water from Naperville Water System. Naperville Water System has no health-based violations since 2016. EPA testing found no PFAS above the federal limits. Federal data can't tell you about your own pipes: lead comes from service lines and plumbing, so test your tap if your home was built before 1986. For the official word, read the utility's annual Consumer Confidence Report.
Does Naperville water have PFAS?
EPA tested Naperville Water System for 29 PFAS between Jan 2024 and Oct 2024 and none were detected above the reporting limits (about 2 to 20 ppt depending on the chemical).
What is the lead level in Naperville water?
The most recent 90th-percentile lead result for Naperville Water System is 6.1 ppb, for the monitoring period that began Jan 2026 (still in progress). The federal action level is 15 ppb, falling to 10 ppb in November 2027. The 90th percentile means 9 in 10 homes sampled were at or below this number. Individual homes can be higher.
Check these numbers yourself
Every figure on this page comes from public EPA records. You don't have to take our word for it:
- EPA's own report for IL0434670: violations, enforcement and inspections, straight from EPA.
- EPA UCMR 5 data: the PFAS and lithium results (search the file for PWSID IL0434670).
- EPA SDWIS download: the lead results, population and violation records we use.
- The utility's annual water quality report (Consumer Confidence Report): ask Naperville Water System at (630) 420-6125, or see EPA's guide to finding it.
Found something that doesn't match? Tell us and we'll check it against EPA's records. How we check our data.
Source: U.S. EPA drinking water records and PFAS testing (UCMR 5). How we read the data.