Santa Clara Water Hardness & Quality Report (2026)
Water Hardness
4.6 grains per gallon
Source
mixed
pH Level
7.5
neutral = 7.0
Lead
0.005 mg/L
✓ Below action level
TDS
187.7 mg/L
Est. Daily Cost
$0.21
energy & soap waste
Source: USGS Water Quality Portal · Updated 2026
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 Santa Clara, your appliances are currently losing 11% efficiency due to mineral buildup.
| Appliance | In Santa Clara | Soft Water City | Efficiency Loss |
|---|---|---|---|
| Kettle | 7 yrs | 8.5 yrs | -18% |
| Washing Machine | 10.7 yrs | 12 yrs | -11% |
| Water Heater | 12.4 yrs | 15 yrs | -17% |
Regional Water Comparison
How Santa Clara compares to its nearest neighbours
| City | Hardness | PFAS (ppt) | Risk | Source |
|---|---|---|---|---|
| ▶ Santa Clara, California | 79 mg/L | 4.3 ppt | 🟡 Moderately Hard | mixed |
| San Jose, California | 189.5 mg/L | 7.5 ppt | 🔴 Very Hard | mixed |
| Campbell, California | 80.5 mg/L | 4.3 ppt | 🟡 Moderately Hard | mixed |
| Sunnyvale, California | 35.5 mg/L | 3 ppt | 🟢 Soft | mixed |
| Cupertino, California | 62 mg/L | 3.8 ppt | 🟡 Moderately Hard | mixed |
National Benchmark
How Santa Clara compares to the USA average
| Benchmark | Hardness | Appliance Risk |
|---|---|---|
| ▶ Santa Clara | 79 mg/L | 🟡 Low |
| USA National Avg | 150 mg/L | 🟠 Moderate |
| Badger Top Rated | 8.5 mg/L | 🟢 None |
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What Makes Santa Clara's Water Unique?
Local geology and source profile
Santa Clara, California — the hub of Silicon Valley — receives its municipal water supply through the City of Santa Clara Water and Sewer Services, drawing from Santa Clara Valley Water District (Valley Water) regional supplies and direct connections to the San Francisco Public Utilities Commission (SFPUC) Hetch Hetchy Regional Water System, which delivers treated Tuolumne River water from Hetch Hetchy Reservoir in Yosemite National Park via the Hetch Hetchy Aqueduct. Valley Water also delivers blended local groundwater from the Santa Clara Valley Groundwater Basin and imported State Water Project water. Water hardness measures 79 mg/L — classified as moderately soft.
Santa Clara's moderately soft supply reflects the dominance of the Hetch Hetchy Aqueduct water in the blended supply. Hetch Hetchy water derives from Tuolumne River snowmelt originating in Yosemite National Park — draining the Sierra Nevada Tuolumne Batholith (Cretaceous granodiorite) and associated Triassic metavolcanic rocks of the Foothills, among the softest natural water sources in North America. Valley Water's local groundwater fraction, drawn from the Santa Clara Valley alluvial aquifer (recharged by Coyote Creek, Los Gatos Creek, and Guadalupe River from the Diablo Range Coast Range), adds some moderate hardness to the blended system. The resulting supply is moderately soft, typical of the South Bay region.
With hardness at 79 mg/L, Santa Clara residents experience minimal scale challenges. Faucet aerators and showerheads rarely need descaling. Soap and shampoo lather well. Dishwashers produce clean glassware with light rinse-aid use. Hot water systems remain largely scale-free. City of Santa Clara Water and Sewer Services and Valley Water consistently deliver water meeting all California SWRCB and EPA Safe Drinking Water Act requirements.
Geology & Source: Mixed supply from Hetch Hetchy Aqueduct (Tuolumne River, Sierra Nevada) via the San Francisco Public Utilities Commission (SFPUC) and Santa Clara Valley Water District (Valley Water) local surface and groundwater — Tuolumne River Precambrian–Mesozoic granodiorite snowmelt produces very soft Hetch Hetchy water; the Valley Water blended fraction adds some hardness to produce moderately soft 79 mg/L.