Water Quality in San Anselmo, CA: No Violations — Grade C
Grade C · Score 64/100 · 1 water system · Updated 2026-05-03
San Anselmo's water has moderate compliance issues. Residents in affected areas should consider filtration.
Data: EPA Safe Drinking Water Information System (SDWIS) Last verified: 2026-05-03
Federal EPA data for San Anselmo, CA shows no violations on record — 1 system, all clear.
Water Quality by ZIP Code in San Anselmo
Water quality varies across San Anselmo's 2 ZIP codes. Check your specific ZIP for detailed contaminant data.
| ZIP Code | Grade | Score | Violations | Health | |
|---|---|---|---|---|---|
| 94960 | C | 55 | 0 | 0 | View report → |
| 94979 | B | 73 | 0 | 0 | View report → |
Water Quality Overview
San Anselmo, California receives a water quality grade of C with an overall score of 64 out of 100, based on EPA compliance data from the Safe Drinking Water Information System (SDWIS).
No EPA violations have been recorded for the 1 water system serving San Anselmo. This is a positive indicator, though it does not guarantee the absence of all contaminants — some substances (like PFAS) are not yet fully regulated.
What Grade C Means
A grade of C indicates moderate compliance issues. San Anselmo's water systems have some violations that warrant attention. While the water may still be safe for most people, residents in affected ZIP codes should consider additional testing or filtration.
Lead Levels
Lead testing data for San Anselmo is currently being collected. The EPA requires all community water systems to test for lead under the Lead and Copper Rule.
With 90% of homes built before 1986, San Anselmo has a higher-than-average risk of lead from older plumbing. Lead solder was banned in 1986, and homes built before this date may have lead in pipes, solder joints, or fixtures.
Water Systems Serving San Anselmo
San Anselmo is served by 1 community water system regulated under the Safe Drinking Water Act. These systems collectively serve approximately 300 people across 2 ZIP codes.
Each water system is identified by a Public Water System ID (PWSID) and is required to:
- Test for over 90 regulated contaminants on a regular schedule
- Report results to the EPA and state regulators
- Issue an annual Consumer Confidence Report (CCR) to all customers
- Take corrective action when violations occur
How to Check Your Water in San Anselmo
Enter your ZIP code on ZipCheckup to see your specific water system data, including contaminant levels, violation history, and safety scores
Request your CCR — your water utility must provide an annual Consumer Confidence Report with detailed test results for all monitored contaminants
Get a home test — certified kits cost $20–$50 and test for lead, bacteria, and common contaminants. Professional lab tests ($150–$400) cover a broader panel
Consider filtration — NSF-certified filters can remove specific contaminants. Reverse osmosis removes the broadest range; activated carbon is effective for chlorine and many organics
Check for advisories — monitor your local utility website and local news for boil water advisories or system alerts
San Anselmo vs. Nearby California Cities
How San Anselmo's water quality compares to similar cities in California:
| City | Grade | Violations | Systems | Population |
|---|---|---|---|---|
| San Anselmo | C | 0 | 1 | 300 |
| Clearlake Oaks | C | 0 | 1 | 300 |
| Fairfax | C | 0 | 1 | 300 |
| Glenhaven | A | 0 | 1 | 300 |
Common Questions About San Anselmo Water
These are the most common questions residents search for about water quality in San Anselmo, California:
Is San Anselmo water hard or soft? Water hardness varies by source. San Anselmo's 1 water system uses a single source. Check your ZIP code report for specific hardness data.
Can I drink San Anselmo tap water? San Anselmo's water receives a grade of C (64/100). No health-based violations have been recorded, but home testing is always recommended.
What is the best water filter for San Anselmo? A NSF/ANSI 53-certified filter for lead removal is a good general choice. See our Water Filter Matcher for personalized recommendations.
San Anselmo vs. California Average
Understanding how San Anselmo compares to the broader California average helps contextualize your local water quality. Factors like water source, treatment methods, and infrastructure age all contribute to differences between cities in the same state.
To see how individual neighborhoods compare, check the ZIP code reports below — water quality can vary significantly even within San Anselmo.
ZIP Codes in San Anselmo
San Anselmo spans 2 ZIP codes. Each ZIP code has its own water quality profile based on the specific water system serving that area. Check each ZIP code for detailed contaminant data, violation history, and system information.
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
- Enforcement: EPA ECHO database
- Filter recommendations: NSF/ANSI certified products
Updated daily.