States › Illinois › DuPage County

DuPage County, IL Water Quality

Water quality data for 28 public water systems serving DuPage County, Illinois — based on EPA SDWIS enforcement records, lead testing results, and health-based violation history.

📅 2026 Report 🔄 Data updated 2026 Q2 📍 28 water systems · 30 cities
✅
Generally Safe — Most Systems Performing Well

The majority of water systems have no active violations and lead levels well below the federal action level.

B

DuPage County Earns a B

DuPage County: 30 communities across 28 water systems. 100.0% have no open violations.

  • Median lead where detected: 1.45 ppb
  • 17 communities with a lead detection, 13 reporting none detected
  • 0 communities with PFAS above the federal limit
  • 24 with significant inspection deficiencies
  • 100.0% of communities have no open violations
1.45 ppb
Median Lead Level
County-wide, 90th percentile
28
Water Systems
Active CWS & NTNCWS
100%
Violation-Free
No active violations on record
How we grade counties: MyWaterIQ uses EPA SDWIS enforcement data — actual MCL violations and lead test results — not the aspirational MCLG targets used by some sites. A grade reflects real compliance history, not theoretical risk. Learn more →

Cities by Water Quality

⭐ Best Performing
  • Addison
    Not detected
    No federal limits exceeded on record
    A
  • Glen Ellyn
    2.75 ppb
    No federal limits exceeded on record
    A
  • West Chicago
    0.93 ppb
    No federal limits exceeded on record
    A
  • Wood Dale
    Not detected
    No federal limits exceeded on record
    A
  • Wayne
    0.93 ppb
    No federal limits exceeded on record
    A
⚠ Needs Attention
  • Naperville
    7.10 ppb
    1 significant inspection deficiency
    B
  • Elmhurst
    7.21 ppb
    2 significant inspection deficiencies
    B
  • Lombard
    11.20 ppb
    1 significant inspection deficiency
    B
  • Villa Park
    8.90 ppb
    2 significant inspection deficiencies
    B
  • Lisle
    7.10 ppb
    1 significant inspection deficiency
    B
County Lead Level — Median 1.45 ppb
Based on most recent 90th percentile lead tests across all reporting systems
0 ppb5 ppb10 ppb15 ppb
County median: 1.45 ppb — 9.7% of the federal action level
Systems by Lead Level
Under 5 ppb
12
5 – 10 ppb
4
10 – 15 ppb
1
No Data
13

All Cities in DuPage County

Naperville 7.10 ppb B
Wheaton Not detected A
Downers Grove 2.10 ppb B
Elmhurst 7.21 ppb B
Lombard 11.20 ppb B
Carol Stream 0.84 ppb A
Bartlett Not detected A
Addison Not detected A
Glendale Heights Not detected A
Woodridge Not detected A
Glen Ellyn 2.75 ppb A
West Chicago 0.93 ppb A
Westmont Not detected B
Roselle 1.19 ppb A
Bloomingdale 1.25 ppb A
Darien Not detected A
Villa Park 8.90 ppb B
Bensenville Not detected A
Hinsdale 1.45 ppb A
Wood Dale Not detected A
Lisle 7.10 ppb B
Burr Ridge Not detected A
Itasca 0.86 ppb A
Warrenville 1.65 ppb A
Willowbrook Not detected A
Clarendon Hills Not detected B
Winfield Not detected A
Oak Brook 0.83 ppb A
Oakbrook Terrace 1.30 ppb B
Wayne 0.93 ppb A
Showing 30 cities
No active violations Active violations

About DuPage County Drinking Water

DuPage County is served by 28 water systems covering 30 communities. No community here has an open violation on record.

Of the communities reporting lead results, 17 recorded a detection, with a median of 1.45 ppb — 10% of the federal action level. 13 reported none detected, which means below the laboratory limit rather than an absence of lead.

No community here has PFAS above the federal limit on record. State inspectors recorded significant deficiencies at 24 of them.

Frequently Asked Questions

Is DuPage County tap water safe to drink?▼
No community in DuPage County has an open violation on record. No community has PFAS above the federal limit on record.
What is the lead level in DuPage County?▼
Among communities with a detection the median is 1.45 ppb, 10% of the 15 ppb action level. 13 reported none detected and 0 reported no result.
How many water systems serve DuPage County?▼
28 community water systems serve 30 communities here.
← Back to Illinois water quality overview