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Water Quality Report

Darien, IL

DuPage County · 35,146 residents · 7 water systems

4

Contaminants detected

0

PFAS compounds

638

Hardness (mg/L)

0

Above legal limits

6

Above health guidelines

Darien drinking water comes from a mix of groundwater and surface water sources. Based on the most recent monitoring data, 4 contaminants have been detected in the water supply, including Lead, Copper, Total Trihalomethanes, Haloacetic Acids (HAA5). PFAS testing has been conducted with no detections. Water hardness is 638 mg/L (very hard), which can cause scale buildup in appliances and reduce soap effectiveness.

Contaminants detected in Darien water

Detection does not necessarily mean unsafe levels. See individual reports for concentrations and EPA limits.

Lead0 / 0.015 mg/L
0% of EPA limit
Copper26.1 / 1300 ug/L
2% of EPA limit
Total Trihalomethanes52.3 / 80 ug/L
65% of EPA limit
Haloacetic Acids (HAA5)22.1 / 60 ug/L
37% of EPA limit
PFAS (tested — none detected)
Microplastics (not routinely tested)

Water systems serving Darien

DARIEN

21,751 servedSurface water4 contaminants
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SOUTHEAST REGIONAL WATER FACILITY

6,940 servedSurface water19 contaminants1 above guideline
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GLEN ELLYN HEIGHTS SUBDIVISION

1,931 servedSurface water19 contaminants2 above guidelines
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STEEPLE RUN SBDV

1,931 servedSurface water20 contaminants2 above guidelines
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YORK TOWNSHIP WATER SYSTEM

1,423 servedSurface water4 contaminants
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NORTH REGIONAL WATER FAC

770 servedGroundwater20 contaminants1 above guideline
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HOBSON VALLEY WATER SYSTEM

400 servedSurface water3 contaminants
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Other cities in DuPage County

Water quality reports for nearby Illinois communities.

AddisonBensenvilleBloomingdaleBurr RidgeCarol StreamChicagoClarendon HillsDowners GroveElmhurstGlen EllynGlendale HeightsGlenview

Frequently asked questions

Is Darien, IL tap water safe to drink?
Darien tap water meets EPA legal standards (Maximum Contaminant Levels). However, 6 contaminants are present above independent health guidelines, which are often stricter than legal limits. 4 contaminants have been detected in the water supply, including Lead, Copper, Total Trihalomethanes, Haloacetic Acids (HAA5). View the detailed report for each water system to see specific levels and how they compare to both legal limits and health guidelines.
What contaminants are in Darien water?
Monitoring has detected 4 contaminants in Darien's water supply: Lead, Copper, Total Trihalomethanes, Haloacetic Acids (HAA5). 6 exceed health guidelines. See individual system reports for concentrations relative to EPA limits.
Does Darien water have PFAS?
Darien's water has been tested for PFAS compounds with no detections. Testing was conducted as part of the EPA's Unregulated Contaminant Monitoring Rule (UCMR5) program.
Is Darien water hard?
Yes. Darien water has a hardness of 638 mg/L (very hard). Hard water is not a health concern but can cause scale buildup in water heaters and appliances, reduce soap effectiveness, and leave mineral deposits. Water softeners or conditioning systems can address hardness.
Where does Darien get its drinking water?
Darien's drinking water comes from a combination of groundwater and surface water sources. The water is treated and tested according to Illinois EPA and EPA requirements before distribution. Darien is served by 7 water systems, the largest being DARIEN (serving 21,751 people).

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