Loading water data...
Not health advice. Contact your local water utility for concerns.
Data from EPA Water Quality Reports. For official information, contact your water utility or health department.
Water quality data for 7 cities serving 427,023 residents
DuPage County in Illinois has an average water quality score of 82/100 (Grade B+) based on analysis of 7 municipal water systems. The county's water systems serve approximately 427,023 residents.
Overall, DuPage County demonstrates good water quality standards. 5 of 7 cities exceed the county average, with Naperville leading with a score of 97/100.
7 cities ranked by water quality score
| Rank | City | Score | Grade | Population |
|---|---|---|---|---|
| 1 | Naperville Top concern: Chromium (10.5% of limit) | 97 | A+ | 152,531 |
| 2 | Elmhurst Top concern: Haloacetic Acids (34.9% of limit) | 85 | A- | 48,733 |
| 3 | Carol Stream Top concern: Fluoride (19.1% of limit) | 84 | B+ | 42,697 |
| 4 | Wheaton Top concern: Haloacetic Acids (44% of limit) | 82 | B+ | 55,114 |
| 5 | Downers Grove Top concern: Total Trihalomethanes (19.5% of limit) | 82 | B+ | 46,445 |
| 6 | Lombard Top concern: Haloacetic Acids (32.9% of limit) | 71 | B- | 44,299 |
| 7 | Addison Top concern: Haloacetic Acids (43.9% of limit) | 70 | B- | 37,204 |
Top detected contaminants across county water systems
| Contaminant | Avg Level | Max Level | EPA Limit | % of Limit | Cities |
|---|---|---|---|---|---|
| Haloacetic Acids | 18.25 ug/L | 26.376 ug/L | 60 ug/L | 30.4% | 6 |
| Total Trihalomethanes | 20.405 ug/L | 31.819 ug/L | 80 ug/L | 25.5% | 6 |
| Fluoride | 0.771 mg/L | 0.965 mg/L | 4 mg/L | 19.3% | 6 |
| Arsenic | 0.002 mg/L | 0.003 mg/L | 0.01 mg/L | 16.8% | 5 |
| Nitrite | 0.152 mg/L | 0.247 mg/L | 1 mg/L | 15.2% | 5 |
| Lead | 0.002 mg/L | 0.004 mg/L | 0.015 mg/L | 12.4% | 7 |
| Mercury | 0 mg/L | 0.001 mg/L | 0.002 mg/L | 11.7% | 6 |
| Nitrate | 0.981 mg/L | 2.997 mg/L | 10 mg/L | 9.8% | 7 |
Recent violations across county water systems
Water quality in DuPage County, Illinois reflects the region's unique combination of water sources, treatment infrastructure, and environmental factors. Our comprehensive analysis examines 7 municipal water systems serving a combined population of over 427,023 residents.
The county shows strong water quality performance, with scores ranging from 70/100 in Addison to 97/100 in Naperville. This 27-point spread indicates significant variation in water quality across the county, suggesting different water sources or treatment approaches.
The most prevalent contaminants detected across DuPage County water systems include Haloacetic Acids, Total Trihalomethanes, Fluoride. All monitored contaminants remain within acceptable levels relative to EPA Maximum Contaminant Levels (MCLs).
DuPage County's water quality is generally good. Residents can feel confident in their tap water quality, though those with specific health concerns or sensitivity to certain contaminants may still benefit from filtration. Regular review of your city's annual Consumer Confidence Report is recommended.
DuPage County has an average water quality score of 82/100 (Grade B+) based on analysis of 7 municipal water systems serving 427,023 residents.
Naperville has the highest water quality score in DuPage County at 97/100. View the detailed report for Naperville.
Most cities in DuPage County have water that meets EPA standards. However, a water filter can provide additional protection and improve taste. The need depends on your specific city and any personal health considerations.
Click on any city in the rankings table above to view its detailed water quality report, including contaminant levels, EPA compliance history, and filter recommendations.