Is tap water safe in Stockton?

EPA SDWIS shows no active health-based violation in this profile's reporting window. That is not the same as proving every contaminant is absent, and federal data can lag state and utility records.

How hard is the water in Stockton, CA?

Nearby USGS observations produce an estimate of 290 ppm (17 grains per gallon), classified as very hard. This is not a tap measurement.

Do I need a water softener in ZIP code 95212?

At 290 ppm, a correctly sized whole-house softener can reduce scale buildup and hard-water spotting. Treatment for hardness does not remove all health-related contaminants.

City water profile

Stockton water quality

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

Median indexed hardness

271PPM

11 indexed ZIPs

Range 254–290 PPM

State comparison: 82 PPM above
State hardness rank: #41 of 242
Matched utilities: 2
Active health records: 0

City summary

What the indexed records say

Stockton has 11 published ZIP profiles across San Joaquin County. The indexed median is 271 PPM, compared with 189 PPM across California.

Among the 242 Californiacities with an indexed median, Stockton ranks #41from highest to lowest. Across all 678 state ZIP profiles, available estimates run from 3.3to 728.5 PPM.

The 254–290 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 hard11 ZIPs

11 of 11 ZIP profiles have a hardness estimate. Bars count ZIP profiles, not households or laboratory samples.

Evidence quality

Distance, dates, and confidence

Median nearest distance: 12.7 miles
Profiles with evidence: 11/11

Confidence labels

High: 0Moderate: 11Low: 0

City Of Stockton

PWSID CA3910012

Surface water

System population served: 191,302
Last reported: Jun 22, 2026

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

Cdcr California Health Care Facility

PWSID CA3910803

Surface water

System population served: 5,551
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.

Record	System	Period	Status
Nitrate	CA3910012	Jan 1, 2024	Resolved
TTHM	CA3910012	Apr 1, 2023	Resolved · health-based
TTHM	CA3910803	Apr 1, 2023	Resolved · health-based
TTHM	CA3910012	Jan 1, 2023	Resolved · health-based
TTHM	CA3910803	Jan 1, 2023	Resolved · health-based
TTHM	CA3910803	Oct 1, 2022	Resolved · health-based
Lead and Copper Rule	CA3910012	Oct 1, 2021	Resolved

Practical next steps

Move from index to evidence

1. Open your ZIP. Check distance, dates, confidence, and the associated utility.
2. Read the current CCR. Confirm source water, detections, limits, ranges, and notices.
3. Test the tap when needed. Confirm health concerns or treatment sizing with the right method.

Continue comparing

Other California communities

Escalon

San Joaquin County

175 PPM median

Lathrop

San Joaquin County

256 PPM median

Lodi

San Joaquin County

287 PPM median

Manteca

San Joaquin County

268 PPM median

Ripon

San Joaquin County

178 PPM median

Tracy

San Joaquin County

264 PPM median

Search all 242 California cities →

Questions people ask

About water in Stockton

Is the water hard?

The indexed city median is 271 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.