City water profile
Compare local ZIP estimates, evidence quality, associated public systems, and compliance history for Norwalk, Connecticut.
Median indexed hardness
92PPM
5 indexed ZIPs
Range 91–93.1 PPM
City summary
Norwalk has 5 published ZIP profiles across Fairfield County. The indexed median is 92 PPM, compared with 53 PPM across Connecticut.
Among the 52 Connecticutcities with an indexed median, Norwalk ranks #5from highest to lowest. Across all 98 state ZIP profiles, available estimates run from 42.8to 114 PPM.
The 91–93.1 PPM range shows how much the available ZIP estimates vary within the city label.
Hardness distribution
5 of 5 ZIP profiles have a hardness estimate. Bars count ZIP profiles, not households or laboratory samples.
Evidence quality
Confidence labels
Observation window: Jan 4, 2016 to Jun 8, 2026.
ZIP directory
Open a ZIP for site-level provenance and measurements.
ZIP code
92.4 PPM
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ZIP code
91 PPM
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ZIP code
92 PPM
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ZIP code
92.4 PPM
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ZIP code
93.1 PPM
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Public water systems
PWSID CT0150011
The system names this served city; Census place overlap links the city to this ZCTA.
PWSID CT1030021
The system names this served city; Census place overlap links the city to this ZCTA.
PWSID CT1030011
The system names this served city; Census place overlap links the city to this ZCTA.
PWSID CT0350011
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.
| Record | System | Period | Status |
|---|---|---|---|
| Consumer Confidence Rule | CT1030021 | Aug 10, 2024 | Resolved |
| Consumer Confidence Rule | CT1030021 | Jul 1, 2024 | Resolved |
| Lead and Copper Rule | CT1030011 | Dec 30, 2021 | Resolved |
| Arsenic | CT0150011 | Jan 1, 2021 | Archived |
| Barium | CT0150011 | Jan 1, 2021 | Archived |
| Chromium | CT0150011 | Jan 1, 2021 | Archived |
| CYANIDE | CT0150011 | Jan 1, 2021 | Archived |
| Antimony, Total | CT0150011 | Jan 1, 2021 | Archived |
| Beryllium, Total | CT0150011 | Jan 1, 2021 | Archived |
| Selenium | CT0150011 | Jan 1, 2021 | Archived |
Practical next steps
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Questions people ask
The indexed city median is 92 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.