Mill Valley, CA Water Safety: 64/100 (2026)
2 ZIP codes · 2 water systems · Updated 2026-06-03
Unlike higher-rated cities in CA, Mill Valley carries a fair number of documented violations — the pattern of compliance gaps keeps the city in the middle tier of EPA safety rankings.
How Mill Valley Compares
Data: EPA SDWIS Last verified: 2026-06-03
What You Should Know About Mill Valley Water
- Estimated remediation: $1,200 per household.
- CDC health risk index: 10.78.
Who Supplies Your Water in Mill Valley
Across Mill Valley, CA, residential water comes from 2 primary utilities rather than a single consolidated provider. Each system operates independently — managing its own distribution infrastructure, rate schedules, and EPA compliance filings. Federal records track 2 water systems in the area, with these top providers accounting for the majority of residential connections.
Overview
We track water quality and home safety data for 2 ZIP codes in Mill Valley, California (population ~32,349), covering 2 community water systems serving approximately 205,342 people region-wide.
No EPA violations recorded across any ZIP codes in Mill Valley — an excellent indicator of water quality.
Home Safety Score
Average Home Safety Score for Mill Valley: 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
Mill Valley water systems draw from: Surface water.
Lead & Copper
- Lead data: not yet available for Mill Valley
- 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 |
|---|---|---|---|
| 94941 | C | MARIN MUNICIPAL WATER DISTRICT | 186,895 |
| 94942 | B | MARIN MUNICIPAL WATER DISTRICT | 186,895 |
All ZIP Codes in Mill Valley
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.
Health Outcomes in Mill Valley
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
Cost Context: What Remediation Means for Mill Valley Homeowners
In Mill Valley, 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 Mill Valley are relatively low compared to home values. The $800–$1,800 estimated range is a small fraction of median property value. Home values are 169% above the California average.
Flood & Climate Risk in Mill Valley
389 FEMA flood insurance claims are on file for Mill Valley, and 50% of local ZIP codes fall within federally designated flood zones — enough to put flood exposure on the planning radar, though short of the concentrated-risk threshold where treatment-system vulnerability becomes a primary consideration.
Mill Valley has a moderate flood history with 389 FEMA claims averaging $5,166 per payout. 50% 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>$1,200</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 Mill Valley
- 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 Mill Valley, CA