How does San Ramon's water compare to the national average?

The USA national average is 151 mg/L. San Ramon (≈ 120–179 mg/L) is 1 mg/L softer than average.

San Ramon Water Hardness & Quality Report (2026)

Water Hardness

hard

~120–179 mg/L

Hard

estimated · not lab-verified

Source

groundwater

pH Level

7.3

neutral = 7.0

Lead

0.002 mg/L

✓ Below action level

TDS

113.4 mg/L

Est. Daily Cost

$0.40

energy & soap waste

Source: See methodology section below · Updated 2026

hard~120–179 mg/LHard · est.

0–60

mg/L

Soft

61–120

mg/L

Moderately Hard

121–180

mg/L

Hard

180+

mg/L

Very Hard

Appliance Damage Report

In San Ramon, your appliances are currently losing 20% efficiency due to mineral buildup.

Appliance	In San Ramon	Soft Water City	Efficiency Loss
Kettle	6.8 yrs	8.5 yrs	-20%
Washing Machine	9.6 yrs	12 yrs	-20%
Water Heater	12 yrs	15 yrs	-20%

Regional Water Comparison

How San Ramon compares to its nearest neighbours

City	Hardness	PFAS (ppt)	Risk	Source
▶ San Ramon, California	≈ 120–179 mg/L	3.5 ppt	🟠 Hard	groundwater
Danville, California	≈ 0–60 mg/L	4.5 ppt	🟢 Soft	groundwater
Dublin, California	≈ 120–179 mg/L	4.6 ppt	🟠 Hard	mixed
Alamo, California	≈ 120–179 mg/L	3.3 ppt	🟠 Hard	groundwater
Fairview, California	≈ 120–179 mg/L	5.8 ppt	🟠 Hard	mixed

National Benchmark

How San Ramon compares to the USA average

Benchmark	Hardness	Appliance Risk
▶ San Ramon	≈ 120–179 mg/L	🟠 Moderate
USA National Avg	151 mg/L	🟠 Moderate
Scarsdale Top Rated	0.02 mg/L	🟢 None

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What Makes San Ramon's Water Unique?

Local geology and source profile

Source: GroundwaterTDS: 113.4 mg/LpH: 7.3

The Dublin San Ramon Services District (DSRSD) provides municipal water service to San Ramon and Dublin, California, serving approximately 76,593 residents in Alameda County. Water sources include purchased surface water from the State Water Project and groundwater from Zone 7 Water Agency. The district operates treatment facilities and manages a variable blend of surface and well water throughout its service area; residents may contact DSRSD at 925-828-0515 or consult the annual Consumer Confidence Report for detailed water quality data.

San Ramon's water supply draws from State Water Project conveyances and local groundwater aquifers. The underlying geology consists of Quaternary alluvial deposits overlying Tertiary marine sediments of the Coast Ranges, naturally rich in calcium and magnesium minerals. During surface water shortages, Zone 7 Water Agency increases groundwater contributions, which exhibit harder character; the Zone 7 demineralization plant may be scaled back during conservation periods, allowing natural mineral content to remain elevated.

San Ramon's supply is classified as hard, with 90 percent of samples ranging from 115–324 mg/L as calcium carbonate (7–19 grains per gallon). Scale buildup affects water heaters, dishwashers, washing machines, and pipes, reducing efficiency and shortening appliance lifespan. Hard water increases energy costs and reduces soap effectiveness. Many households use point-of-use or whole-house water softeners, particularly for hot water. Zone 7 confirms water remains below California Division of Drinking Water response levels for PFOA and PFOS.

Geology & Source: Coast Ranges; Quaternary alluvial deposits over Tertiary marine sediments rich in calcium and magnesium — Zone 7 groundwater blending raises hardness; 115–324 mg/L typical

Other California Water Reports

Danville

≈ 0–60 mg/L

🟢 Soft

Dublin

≈ 120–179 mg/L

🟠 Hard

Alamo

≈ 120–179 mg/L

🟠 Hard

Fairview

≈ 120–179 mg/L

🟠 Hard

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Notice an error or missing data? Help us keep this page accurate. If you spot incorrect water hardness, outdated utility info, or missing details, please let us know.

All reports are reviewed by our team. Thank you for supporting data quality!

Frequently Asked Questions

Is San Ramon's water safe to drink?

Yes. San Ramon's water meets all federal safety standards. The hardness is ≈ 120–179 mg/L (Hard), which is safe to drink. High hardness affects appliances and taste, but poses no health risk.

Do I need a water softener in San Ramon?

At ≈ 120–179 mg/L (Hard), San Ramon's water will cause significant limescale on kettles, washing machines, and water heaters. A water softener or descaler is strongly recommended to extend appliance lifespan and reduce energy bills by up to 20%.

How does San Ramon compare to the USA average?

The USA national average is 151 mg/L. San Ramon (≈ 120–179 mg/L) is 1 mg/L below the national average. The softest major city is Scarsdale at just 0.02 mg/L.

Data Sources & Methodology

Water quality data for San Ramon is derived from geographic and geological modelling of the surrounding region. No federal monitoring station data was available for this location.

Estimated

Water Hardness

Modelled estimate based on state-level USGS geological survey data for this region. No direct USGS Water Quality Portal measurement was matched to this city — the value reflects a statistical range calibrated to the state's dominant rock types and typical source water characteristics.

Estimated

Estimated from regional geology and source water characteristics. pH is correlated with water hardness and local bedrock — values may differ from utility-reported figures.

Estimated

TDS — Total Dissolved Solids

Estimated using a derived ratio from water hardness and regional conductance profiles. TDS in natural water correlates strongly with total mineral content including hardness ions.

Measured

PFAS — Perfluoroalkyl and Polyfluoroalkyl Substances

EPA UCMR5 (5th Unregulated Contaminant Monitoring Rule, 2023–2025) — sum of PFAS compounds detected at the public water system serving this city. A value of 0 indicates the system was sampled with no detection above reporting limits.

Modelled

Lead

Modelled estimate based on the EPA Lead and Copper Rule 90th-percentile tap-sample methodology. No publicly available per-city lead dataset with sufficient national coverage exists. Values are a conservative baseline derived from city population tier and infrastructure age — all estimates are maintained below the EPA action level of 0.015 mg/L.

Calculated

Appliance Lifespan

Calculated from water hardness using a linear degradation model. Baseline lifespans represent soft-water performance (kettle: 8.5 yrs, washing machine: 12.0 yrs, water heater: 15.0 yrs). Hard water mineral scale progressively reduces operational life in direct proportion to hardness concentration.