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City water profile

Sunnyvale water quality

Compare local ZIP estimates, evidence quality, associated public systems, and compliance history for Sunnyvale, California.

Median indexed hardness

272PPM

4 indexed ZIPs

Range 272–273 PPM

State comparison
83 PPM above
State hardness rank
#35 of 242
Matched utilities
1
Active health records
0

City summary

What the indexed records say

Sunnyvale has 4 published ZIP profiles across Santa Clara County. The indexed median is 272 PPM, compared with 189 PPM across California.

Among the 242 Californiacities with an indexed median, Sunnyvale ranks #35from highest to lowest. Across all 678 state ZIP profiles, available estimates run from 3.3to 728.5 PPM.

The 272–273 PPM range shows how much the available ZIP estimates vary within the city label.

Hardness distribution

How local ZIP estimates compare

Soft0 ZIPs
Moderately hard0 ZIPs
Hard0 ZIPs
Very hard4 ZIPs

4 of 4 ZIP profiles have a hardness estimate. Bars count ZIP profiles, not households or laboratory samples.

Evidence quality

Distance, dates, and confidence

Median nearest distance
5.3 miles
Profiles with evidence
4/4

Confidence labels

High: 0Moderate: 4Low: 0

Observation window: Jan 13, 2016 to Jun 3, 2026.

ZIP directory

Water reports in Sunnyvale

Open a ZIP for site-level provenance and measurements.

ZIP code

94085

Very Hard

272 PPM

Nearest site
4.8 mi
Confidence
Moderate

View full ZIP evidence →

ZIP code

94086

Very Hard

272 PPM

Nearest site
5 mi
Confidence
Moderate

View full ZIP evidence →

ZIP code

94087

Very Hard

272 PPM

Nearest site
5.6 mi
Confidence
Moderate

View full ZIP evidence →

ZIP code

94089

Very Hard

273 PPM

Nearest site
5.3 mi
Confidence
Moderate

View full ZIP evidence →

Public water systems

Utilities associated with this city

City Of Sunnyvale

PWSID CA4310014

Surface water
System population served
157,566
Last reported
Jun 22, 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.

No violation records are included in the current lookback window.

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 Sunnyvale

Is the water hard?

The indexed city median is 272 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.