City water profile
Compare local ZIP estimates, evidence quality, associated public systems, and compliance history for Lake Oswego, Oregon.
Median indexed hardness
29PPM
2 indexed ZIPs
Range 28.8–28.8 PPM
City summary
Lake Oswego has 2 published ZIP profiles across Clackamas County. The indexed median is 29 PPM, compared with 29 PPM across Oregon.
Among the 21 Oregoncities with an indexed median, Lake Oswego ranks #11from highest to lowest. Across all 56 state ZIP profiles, available estimates run from 15.7to 78.9 PPM.
The 28.8–28.8 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: Jan 5, 2016 to May 19, 2026.
ZIP directory
Open a ZIP for site-level provenance and measurements.
Public water systems
PWSID OR4100457
A municipal system, in-state city, and served county all agree with this Census 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 | OR4100457 | Jul 1, 2025 | Resolved |
| Consumer Confidence Rule | OR4100457 | Jul 1, 2024 | Resolved |
Practical next steps
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Questions people ask
The indexed city median is 29 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.