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Water Hardness in 94086

Sunnyvale, California · Santa Clara County

188 PPM
11 GPG
Hard
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
1 verified treated-water source
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 2024
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 94086

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.
San Jose Water
CA4310011
Moderately Hard
151 PPMsurface water1,039,920 servedVerified — State Lab Tested
Source water: 192 PPM
City Of Sunnyvale
CA4310014
Hard
245 PPMsurface water157,566 servedEstimated — County Avg
City Of Santa Clara
CA4310012
Hard
192 PPMsurface water130,746 servedHigh Confidence — USGS Monitoring
Great Oaks Wc Inc
CA4310022
Very Hard
358 PPMgroundwater110,088 servedHigh Confidence — USGS Monitoring
City Of San Jose - Evg/Edv/Coy
CA4310020
Hard
192 PPMsurface water101,265 servedHigh Confidence — USGS Monitoring
Showing the first 5 systems. Expand to review all matched systems.

Nearby Zip Codes

940871889505118894089188940411889404018895054188940431889505018894024188950021889512918895117188

What This Means For You

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

Hard Water - Treatment Recommended

Your water is hard. Scale buildup is likely affecting your plumbing and appliances, reducing their lifespan and efficiency. A water softener is recommended to protect your home.

Recommended Products

Salt-Based Water Softener
Our PickAFWFilters Fleck 5600SXT 48KAlso GreatWhirlpool WHES40E 40KAlso GreatAFWFilters 64K GrainAlso GreatAFWFilters Iron Pro 2 64KAlso GreatSpringWell Filter + Softener Combo
Salt-Free Water Conditioner
Our PickSpringWell Salt-Free Cartridge
Water Hardness Test Kit
Our PickVarify (150 Strips)Also GreatJNW Direct (150 Strips)
Shower Head Filter
Our PickWeddell DuoAlso GreatAquaBliss SF100Also GreatSprite Pure 7-SettingAlso GreatAqua Earth 20-Stage
Water Softener Salt
Our PickMorton Clean & ProtectAlso GreatDiamond Crystal Bright & Soft

Learn more: Do I Need a Water Softener? | Salt-Based vs Salt-Free | Size Calculator | How to Test Your 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 Sunnyvale, CA (94086).

Submit Your Data

Frequently Asked Questions

Is the water hard in Sunnyvale, CA (94086)?

The average water hardness in 94086 is 188 PPM (11 GPG), which is classified as hard.

Do I need a water softener in 94086?

With hardness of 188 PPM, a water softener is recommended for homes in 94086.

Is hard water in 94086 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 94086?

Zip code 94086 in Sunnyvale, California is served by 15 water systems.

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