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City water profile

Darien water quality

Compare local ZIP estimates, evidence quality, associated public systems, and compliance history for Darien, Illinois.

Median indexed hardness

245PPM

One indexed ZIP

Range 245–245 PPM

State comparison
40 PPM below
State hardness rank
#797 of 913
Matched utilities
1
Active health records
0

City summary

What the indexed records say

Darien has 1 published ZIP profile across Dupage County. The indexed median is 245 PPM, compared with 285 PPM across Illinois.

Among the 913 Illinoiscities with an indexed median, Darien ranks #797from highest to lowest. Across all 1,065 state ZIP profiles, available estimates run from 115to 408 PPM.

Because only one ZIP is represented, the city median and range are the same local estimate. It should not be read as multiple independent samples across the community.

Hardness distribution

How local ZIP estimates compare

Soft0 ZIPs
Moderately hard0 ZIPs
Hard0 ZIPs
Very hard1 ZIP

1 of 1 ZIP profiles have a hardness estimate. Bars count ZIP profiles, not households or laboratory samples.

Evidence quality

Distance, dates, and confidence

Median nearest distance
17.7 miles
Profiles with evidence
1/1

Confidence labels

High: 0Moderate: 1Low: 0

Observation window: Apr 12, 2016 to May 13, 2026.

ZIP directory

Water reports in Darien

Open a ZIP for site-level provenance and measurements.

ZIP code

60561

Very Hard

245 PPM

Nearest site
17.7 mi
Confidence
Moderate

View full ZIP evidence →

Public water systems

Utilities associated with this city

Darien

PWSID IL0430270

Surface water
System population served
21,751
Last reported
May 27, 2026

The system names this served city; Census place overlap links the city to this ZCTA.

Compliance history

What EPA records show

No active health-based violation appears among the associated systems in the represented EPA reporting quarter. This does not mean every contaminant was tested at every tap.

RecordSystemPeriodStatus
Consumer Confidence RuleIL0430270Jul 1, 2024Resolved

Practical next steps

Move from index to evidence

  1. 1. Open your ZIP. Check distance, dates, confidence, and the associated utility.
  2. 2. Read the current CCR. Confirm source water, detections, limits, ranges, and notices.
  3. 3. Test the tap when needed. Confirm health concerns or treatment sizing with the right method.

Questions people ask

About water in Darien

Is the water hard?

The indexed city median is 245 PPM. Open the ZIP report to verify the distance and confidence behind that estimate.

Is the tap water safe?

Compliance history is utility-wide and cannot guarantee conditions at every tap. Check current notices and test when address-specific evidence is needed.

Do I need treatment?

Choose treatment only after confirming the problem at the property. A softener targets hardness; contaminant treatment requires a matching, verified performance claim.