San Anselmo, CA Water Safety: 64/100 (2026)
2 ZIP codes · 2 water systems · Updated 2026-06-03
Across San Anselmo, EPA compliance data for CA sits at a moderate level — not alarming, but not uniformly clean across all service areas either.
How San Anselmo Compares
Data: EPA SDWIS Last verified: 2026-06-03
San Anselmo Water: The Quick Version
- Estimated remediation: $1,500 per household.
- CDC health risk index: 10.78.
Water Systems Serving San Anselmo
Structurally, San Anselmo, CA's water supply is divided. Federal data identifies 2 water systems in the area, with 2 providers serving the bulk of residential connections. These utilities operate independently, meaning rate-setting authority and EPA compliance accountability are distributed rather than centralized.
Overview
We track water quality and home safety data for 2 ZIP codes in San Anselmo, California (population ~15,891), covering 2 community water systems serving approximately 187,195 people region-wide.
No EPA violations recorded across any ZIP codes in San Anselmo — an excellent indicator of water quality.
Home Safety Score
Average Home Safety Score for San Anselmo: C (64/100)
The score combines three factors:
| Factor | What It Measures |
|---|---|
| Water Quality | EPA violations and compliance history |
| Lead Levels | 90th percentile lead concentration vs EPA action level |
| Radon Risk | EPA radon zone classification |
Water Sources
San Anselmo water systems draw from: Groundwater.
Lead & Copper
- Lead data: not yet available for San Anselmo
- 0 ZIP codes exceed the EPA lead action level
Radon Risk
Dominant radon zone: Zone 3 (Low Risk)
- Zone 1 (High): 0 ZIP codes
- Zone 2 (Moderate): 0 ZIP codes
- Zone 3 (Low): 2 ZIP codes
Areas with No Violations
| ZIP Code | Safety Score | System | Population |
|---|---|---|---|
| 94960 | C | Marin Municipal Water District | 186,895 |
| 94979 | B | MOREHEAD PARK | 300 |
All ZIP Codes in San Anselmo
Data Sources
- Water quality: EPA Safe Drinking Water Information System (SDWIS)
- Lead/copper: EPA Lead and Copper Rule sampling data
- Radon: EPA Map of Radon Zones
Updated daily.
CDC Health Data for San Anselmo
Source: CDC PLACES (County-level estimates). Water contamination can correlate with respiratory and chronic health conditions.
Compared to National Average
Vertical line = national average. ■ Above national · ■ Below national
San Anselmo: Remediation Cost in Perspective
In San Anselmo, the equity impact of remediation is proportionally small — not the kind of financial commitment that rises to the level of a genuine planning constraint, but a minor share of what most properties here are worth.
Remediation costs in San Anselmo are relatively low compared to home values. The $1,000–$2,150 estimated range is a small fraction of median property value. Home values are 115% above the California average.
Climate-Related Water Risk for San Anselmo
Measured across the NFIP's multi-decade tracking period, San Anselmo shows a moderate flood record — 317 claims and 100% of ZIP codes carrying FEMA flood zone status. For water quality, that combination matters because flood events at this frequency can periodically stress infrastructure: treatment plants, private wells, and distribution systems all face elevated risk during significant flooding.
San Anselmo has a moderate flood history with 317 FEMA claims averaging $21,131 per payout. 100% of ZIP codes fall within FEMA flood zones. Flood events can contaminate drinking water and overwhelm treatment systems.
How flooding affects water quality: Flood events can introduce sewage, agricultural runoff, and industrial chemicals into water supplies. Even after floodwaters recede, contamination can persist in wells and aging infrastructure. Flood damage can add significantly to the estimated <strong>$1,500</strong> remediation cost per household.
Residents in flood-prone areas should consider flood insurance even outside FEMA zones — over 25% of flood claims come from low-to-moderate risk areas. After any flood event, test your water before drinking.
Source: FEMA National Flood Insurance Program (NFIP) claims data, FEMA flood zone designations.
What You Can Do in San Anselmo
- Test your water at home. City-level data shows averages — your tap may differ. NSF-certified test kits cost $20-40 and give results in days.
- Install a certified water filter. An NSF-certified pitcher or under-sink filter removes most common contaminants.
- Check your home's plumbing. Homes built before 1986 may have lead solder in pipes. A licensed plumber can assess your risk.
Deep Dive Reports
Detailed analysis for San Anselmo, CA