San Marino Water Hardness & Quality Report (2026)
Water Hardness
2.6 grains per gallon
Source
mixed
pH Level
7.3
neutral = 7.0
Lead
0.002 mg/L
✓ Below action level
TDS
93 mg/L
Est. Daily Cost
$0.12
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 San Marino, your appliances are currently losing 6% efficiency due to mineral buildup.
| Appliance | In San Marino | Soft Water City | Efficiency Loss |
|---|---|---|---|
| Kettle | 8.1 yrs | 8.5 yrs | -5% |
| Washing Machine | 12 yrs | 12 yrs | — |
| Water Heater | 13.8 yrs | 15 yrs | -8% |
Regional Water Comparison
How San Marino compares to its nearest neighbours
| City | Hardness | PFAS (ppt) | Risk | Source |
|---|---|---|---|---|
| ▶ San Marino, California | 44.5 mg/L | 3.2 ppt | 🟢 Soft | mixed |
| San Gabriel, California | 185.5 mg/L | 7.3 ppt | 🔴 Very Hard | mixed |
| Alhambra, California | 65.5 mg/L | 3.8 ppt | 🟡 Moderately Hard | mixed |
| East San Gabriel, California | 152.5 mg/L | 6.3 ppt | 🟠 Hard | mixed |
| South Pasadena, California | 54.5 mg/L | 3.5 ppt | 🟢 Soft | mixed |
National Benchmark
How San Marino compares to the USA average
| Benchmark | Hardness | Appliance Risk |
|---|---|---|
| ▶ San Marino | 44.5 mg/L | 🟢 None |
| USA National Avg | 150 mg/L | 🟠 Moderate |
| Badger Top Rated | 8.5 mg/L | 🟢 None |
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What Makes San Marino's Water Unique?
Local geology and source profile
San Marino, California, in Los Angeles County — a Los Angeles County city adjacent to Pasadena and Arcadia in the San Gabriel Valley — receives its water from the San Gabriel Valley Municipal Water District, drawing from the State Water Project or local Raymond Basin groundwater (Los Angeles County) through the San Gabriel Valley distribution.
The moderately soft 44.5 mg/L hardness and TDS of 93 mg/L are notably soft for the Los Angeles County area — reflecting San Marino's primary reliance on the Raymond Basin Pleistocene alluvial aquifer and the soft SWP Northern California component rather than the hard MWD Colorado River blend (compare San Marino to Oak Park CA at 138.5 mg/L on heavier MWD-Colorado River blend). The Raymond Basin at Los Angeles County — Pleistocene alluvial fan gravels (slightly calcareous — primary hardness contributor), Quaternary San Gabriel River alluvium (slightly calcareous — secondary contributor), and SWP Northern California supply (soft — dilutant).
At 44.5 mg/L, San Marino's water is moderately soft — light scale forms slowly in appliances, dishwashers remain efficient, and no softening is needed. Semi-annual descaling is appropriate. The PFAS level of 3.2 ppt warrants a certified drinking water filter — the Los Angeles County San Gabriel Valley industrial corridor contribute to San Marino's readings.
Geology & Source: San Marino in Los Angeles County draws from the San Gabriel Valley Municipal Water District on State Water Project or local Raymond Basin groundwater (Los Angeles County, south California) — the Raymond Basin at Los Angeles County is developed in Pleistocene alluvial fan gravels (slightly calcareous) — California Los Angeles County Raymond Basin Pleistocene alluvial supply produces moderately soft water at 44.5 mg/L with TDS 93 mg/L.