Lagunitas, CA Water Safety: 73/100 (2026)
1 ZIP code · 2 water systems · Updated 2026-06-03
Unlike many cities its size in CA, Lagunitas keeps health-based violation rates low — systems here score at or above the state average for tap water safety, with no systemic concerns flagged in the current data set.
How Lagunitas Compares
Data: EPA SDWIS Last verified: 2026-06-03
Lagunitas Water: The Quick Version
- Homes built before 1986: 98% — older plumbing may contain lead solder.
- Estimated remediation: $1,200 per household.
- CDC health risk index: 10.78.
Water Systems Serving Lagunitas
2 water systems are tracked federally in Lagunitas, CA. The top 2 providers collectively serve most residential addresses, but because they operate independently, infrastructure maintenance standards and compliance histories differ from one service zone to another.
Overview
We track water quality and home safety data for 1 ZIP code in Lagunitas, California (population ~540), covering 2 community water systems serving approximately 186,931 people region-wide.
No EPA violations recorded across any ZIP codes in Lagunitas — an excellent indicator of water quality.
Home Safety Score
Average Home Safety Score for Lagunitas: B (73/100)
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
Lagunitas water systems draw from: Groundwater.
Lead & Copper
- Lead data: not yet available for Lagunitas
- 0 ZIP codes exceed the EPA lead action level
Radon Risk
Dominant radon zone: Zone 3 (Low Risk)
Areas with No Violations
| ZIP Code | Safety Score | System | Population |
|---|---|---|---|
| 94938 | B | Marin Municipal Water District | 186,895 |
All ZIP Codes in Lagunitas
- 94938 [B]
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 Lagunitas
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
How Old Is Lagunitas's Housing Stock?
With 98% of homes built before 1986, lead solder in plumbing is a potential concern. The EPA banned lead solder in 1986, but many older homes retain original plumbing.
Source: U.S. Census Bureau American Community Survey (ACS).
Housing Age Profile
Reading the housing age data for Lagunitas — median build year 1957 — the overriding implication is that the plumbing materials inside a typical home here reflect pre-1986 construction standards. In practical terms, that means lead-soldered copper joints are common across much of the housing stock. Where those materials are present, water can leach lead as it moves through joints — a pathway that corrosion control treatment under federal rules is designed to reduce, though it cannot eliminate lead risk where the plumbing materials themselves contain lead.
Over half of homes in Lagunitas were built before 1986, when lead solder was banned. Older plumbing may leach lead into drinking water, especially with corrosive water chemistry.
Source: U.S. Census Bureau ACS B25034.
Lagunitas: Remediation Cost in Perspective
Remediation costs in Lagunitas are small relative to typical property values — the cost-to-value ratio here is favorable.
Remediation costs in Lagunitas are relatively low compared to home values. The $800–$1,800 estimated range is a small fraction of median property value. Home values are 36% above the California average.
Protecting Children from Lead in Lagunitas
Why children are most at risk: The CDC states there is no safe level of lead exposure for children. Children under 6 absorb lead more readily than adults, and even low levels can cause developmental delays, learning difficulties, and behavioral problems.
Pulling a tap sample fills the gap that utility data cannot close, particularly here where 98% of housing dates from the pre-rule era and citywide monitoring sits at or above the regulatory mark in Lagunitas.
Sources: EPA Lead and Copper Rule, U.S. Census Bureau ACS, CDC childhood lead poisoning prevention guidelines.
Climate-Related Water Risk for Lagunitas
Multiple flood events have been recorded for Lagunitas through the NFIP — 9 claims in total, with 100% of ZIP codes in FEMA-designated zones — pointing to a flood exposure profile that merits inclusion in a water quality assessment without reaching high-severity planning territory.
Lagunitas has a moderate flood history with 9 FEMA claims averaging $5,615 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>$1,200</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.
Deep Dive Reports
Detailed analysis for Lagunitas, CA