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Water Hardness in 95370

Sonora, California · Tuolumne County

19 PPM
1.1 GPG
Soft
0Soft60120180300+
Verified — State Lab Tested

Dataset updated March 9, 2026Matched to 15 water systemsTap readings can vary by utility zone, treatment, and plumbing. Methodology

Source context

How this ZIP reading is built

This ZIP reading is built from 15 matched water systems. When more than one system is matched, the displayed value is weighted toward larger known service populations when that data is available.

Source basis
6 verified treated-water sources
15 matched systems total for this ZIP; treated-water reports are prioritized when available.
Water source profile
Primarily surface water
Surface-water hardness can shift with reservoirs, runoff, season, and treatment. This profile is weighted by known population served across matched systems.
Data recency
Report years 2023-2025
Dataset rebuilt March 9, 2026; individual utility reporting years can vary.

Hardness is a mineral-content reading, not a drinking-water safety rating. Use it for scale, appliance, and softener decisions; check your utility report or test your tap before sizing treatment equipment. See how we calculate local readings.

Water Systems Serving 95370

These are the systems matched to this ZIP code. The displayed ZIP value is weighted toward larger known service populations when population data is available.

15 water systems
PWSID is the public water system identifier. Data Source shows whether the hardness value comes from a treated-water report, USGS monitoring, or a local estimate; source year is shown when available.
Tud - Upper Basin Water System
CA5510012
Soft
9 PPMsurface water13,280 servedVerified — State Lab Tested
Source water: 81 PPM
Tud - Sonora/Jamestown Water System
CA5510001
Soft
16 PPMsurface water11,054 servedVerified — State Lab Tested
Source water: 81 PPM
Tud - Columbia Water System
CA5510013
Soft
8 PPMsurface water5,463 servedVerified — State Lab Tested
Source water: 81 PPM
Tud - Ponderosa
CA5510002
Soft
11 PPMsurface water1,767 servedVerified — State Lab Tested
Source water: 81 PPM
Tud - Tuolumne Water System
CA5510003
Soft
11 PPMsurface water1,761 servedVerified — State Lab Tested
Source water: 81 PPM
Showing the first 5 systems. Expand to review all matched systems.

Nearby Zip Codes

953721395310139537913952511995383219534620952475795305129532723952211995222789523319

What This Means For You

Recommendations are based on the displayed ZIP hardness reading. Confirm your tap reading before sizing or buying treatment equipment.

Your Water Is Soft

Your water hardness is in the soft range. You likely don't need a water softener. Enjoy your naturally soft water!

Know your water hardness?

If you've tested your water or have your utility's CCR report, share your reading to help us improve accuracy for Sonora, CA (95370).

Submit Your Data

Frequently Asked Questions

Is the water hard in Sonora, CA (95370)?

The average water hardness in 95370 is 19 PPM (1.1 GPG), which is classified as soft.

Do I need a water softener in 95370?

At 19 PPM, your water is relatively soft. A water softener is generally not necessary.

Is hard water in 95370 safe to drink?

Water hardness itself is a mineral-content reading, not a drinking-water safety rating. Calcium and magnesium are naturally occurring minerals, but you should check your utility's Consumer Confidence Report for contaminant and compliance information.

How many water systems serve 95370?

Zip code 95370 in Sonora, California is served by 15 water systems.

Learn More About Your Water

Water Hardness Scale: PPM and GPG Chart

Use the USGS water hardness scale to compare PPM, GPG, and mg/L levels from soft to very hard water.

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How to Test Water Hardness at Home

Compare free lookups, soap tests, test strips, liquid drop kits, and lab tests for measuring water hardness.

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