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City water profile

Santa Rosa water quality

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

Median indexed hardness

193PPM

6 indexed ZIPs

Range 180–200 PPM

State comparison
4 PPM above
State hardness rank
#96 of 242
Matched utilities
2
Active health records
0

City summary

What the indexed records say

Santa Rosa has 6 published ZIP profiles across Sonoma County. The indexed median is 193 PPM, compared with 189 PPM across California.

Among the 242 Californiacities with an indexed median, Santa Rosa ranks #96from highest to lowest. Across all 678 state ZIP profiles, available estimates run from 3.3to 728.5 PPM.

The 180–200 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
Hard1 ZIP
Very hard5 ZIPs

6 of 6 ZIP profiles have a hardness estimate. Bars count ZIP profiles, not households or laboratory samples.

Evidence quality

Distance, dates, and confidence

Median nearest distance
3.7 miles
Profiles with evidence
6/6

Confidence labels

High: 0Moderate: 6Low: 0

Observation window: Feb 8, 2016 to Jul 31, 2023.

ZIP directory

Water reports in Santa Rosa

Open a ZIP for site-level provenance and measurements.

ZIP code

95401

Very Hard

200 PPM

Nearest site
3.7 mi
Confidence
Moderate

View full ZIP evidence →

ZIP code

95403

Very Hard

198 PPM

Nearest site
4 mi
Confidence
Moderate

View full ZIP evidence →

ZIP code

95404

Very Hard

188 PPM

Nearest site
2.8 mi
Confidence
Moderate

View full ZIP evidence →

ZIP code

95405

Very Hard

183 PPM

Nearest site
3.5 mi
Confidence
Moderate

View full ZIP evidence →

ZIP code

95407

Very Hard

199 PPM

Nearest site
2.4 mi
Confidence
Moderate

View full ZIP evidence →

ZIP code

95409

Hard

180 PPM

Nearest site
5.3 mi
Confidence
Moderate

View full ZIP evidence →

Public water systems

Utilities associated with this city

Santa Rosa, City Of

PWSID CA4910009

Groundwater
System population served
175,396
Last reported
Jun 22, 2026

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

Crystals

PWSID CA4901595

Groundwater
System population served
40
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 Santa Rosa

Is the water hard?

The indexed city median is 193 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.