City water profile
Compare local ZIP estimates, evidence quality, associated public systems, and compliance history for Downers Grove, Illinois.
Median indexed hardness
246PPM
2 indexed ZIPs
Range 245–247 PPM
City summary
Downers Grove has 2 published ZIP profiles across Dupage County. The indexed median is 246 PPM, compared with 285 PPM across Illinois.
Among the 913 Illinoiscities with an indexed median, Downers Grove ranks #776from highest to lowest. Across all 1,065 state ZIP profiles, available estimates run from 115to 408 PPM.
The 245–247 PPM range shows how much the available ZIP estimates vary within the city label.
Hardness distribution
2 of 2 ZIP profiles have a hardness estimate. Bars count ZIP profiles, not households or laboratory samples.
Evidence quality
Confidence labels
Observation window: Apr 12, 2016 to May 13, 2026.
ZIP directory
Open a ZIP for site-level provenance and measurements.
Public water systems
PWSID IL0430300
The system names this served city; Census place overlap links the city to this ZCTA.
Compliance history
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.
No violation records are included in the current lookback window.
Practical next steps
Continue comparing
Questions people ask
The indexed city median is 246 PPM. Open the ZIP report to verify the distance and confidence behind that estimate.
Compliance history is utility-wide and cannot guarantee conditions at every tap. Check current notices and test when address-specific evidence is needed.
Choose treatment only after confirming the problem at the property. A softener targets hardness; contaminant treatment requires a matching, verified performance claim.