San Rafael Water Hardness & Quality Report (2026)
Water Hardness
2.9 grains per gallon
Source
mixed
pH Level
7.3
neutral = 7.0
Lead
0.002 mg/L
✓ Below action level
TDS
107.3 mg/L
Est. Daily Cost
$0.13
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 Rafael, your appliances are currently losing 7% efficiency due to mineral buildup.
| Appliance | In San Rafael | Soft Water City | Efficiency Loss |
|---|---|---|---|
| Kettle | 8 yrs | 8.5 yrs | -6% |
| Washing Machine | 11.8 yrs | 12 yrs | -2% |
| Water Heater | 13.6 yrs | 15 yrs | -9% |
Regional Water Comparison
How San Rafael compares to its nearest neighbours
| City | Hardness | PFAS (ppt) | Risk | Source |
|---|---|---|---|---|
| ▶ San Rafael, California | 49.5 mg/L | 3.5 ppt | 🟢 Soft | mixed |
| San Anselmo, California | 153.5 mg/L | 6.5 ppt | 🟠 Hard | mixed |
| Larkspur, California | 109 mg/L | 5.2 ppt | 🟡 Moderately Hard | mixed |
| Mill Valley, California | 126 mg/L | 5.7 ppt | 🟠 Hard | mixed |
| Novato, California | 110.5 mg/L | 5.3 ppt | 🟡 Moderately Hard | mixed |
National Benchmark
How San Rafael compares to the USA average
| Benchmark | Hardness | Appliance Risk |
|---|---|---|
| ▶ San Rafael | 49.5 mg/L | 🟢 None |
| USA National Avg | 150 mg/L | 🟠 Moderate |
| Badger Top Rated | 8.5 mg/L | 🟢 None |
Bring Badger-quality water to your San Rafael home
Shop water softeners on Amazon.com →
What Makes San Rafael's Water Unique?
Local geology and source profile
San Rafael, California, the Marin County seat north of San Francisco across the Golden Gate — a major Marin County urban center with a large Canal District Latino community, known for its historic architecture and the Frank Lloyd Wright Civic Center — draws its municipal water supply from Nicasio Reservoir, Kent Lake (Lagunitas Creek), and other Marin County reservoirs via the Marin Municipal Water District (MMWD). Water hardness in San Rafael measures 49.5 mg/L — classified as very soft.
San Rafael's very soft supply reflects the Marin County Coast Range watershed's Franciscan Complex geology. The Marin Municipal Water District watershed in west Marin County drains: the Marin Headlands Franciscan Complex (Jurassic–Cretaceous greywacke turbidite, greenstone, chert, and serpentinite — the accretionary wedge terrane of the Marin Peninsula — predominantly calcium-poor); Paleocene–Eocene Nicasio Formation calcareous flysch (some calcareous contribution from the Nicasio Reservoir watershed); and the Coast Range Ophiolite (calcareous serpentinite in places). The dominant calcium-poor Franciscan greywacke and chert of the Marin Coast Range produce the very soft 49.5 mg/L at San Rafael.
With hardness at 49.5 mg/L, San Rafael residents enjoy very soft water with essentially no scale challenges. Marin Municipal Water District consistently delivers water meeting all California SWRCB and EPA Safe Drinking Water Act requirements.
Geology & Source: Reservoir supply from the Nicasio Reservoir and Kent Lake (Lagunitas Creek watershed) via the Marin Municipal Water District (MMWD) — the Marin County Coastal Range (Franciscan Complex greywacke, mélange, and serpentinite) watershed; very soft supply at 49.5 mg/L — reflecting the Marin Coast Range Franciscan Complex's calcium-poor geology.