Nicasio, CA: 1 Health Violation — 94/100 (2026)
1 ZIP code · 2 water systems · Updated 2026-06-03
Residents of Nicasio generally live with tap water that beats the CA safety average on key EPA compliance metrics.
How Nicasio Compares
Data: EPA SDWIS Last verified: 2026-06-03
Key Facts for Nicasio Residents
- Your city's water systems recorded 1 violation in the past 5 years.
- Average lead level: 0.004 mg/L.
- Homes built before 1986: 70% — older plumbing may contain lead solder.
- Estimated remediation: $1,500 per household.
- CDC health risk index: 10.78.
Nicasio's Water Providers
Residential water service in Nicasio, CA is divided among 2 separate utilities, drawn from 2 systems on file with federal regulators.
Overview
We track water quality and home safety data for 1 ZIP code in Nicasio, California (population ~727), covering 2 community water systems serving approximately 61,727 people region-wide.
1 of 1 ZIP code (100%) have recorded EPA violations. 1 health-based violation documented.
Home Safety Score
Average Home Safety Score for Nicasio: A (94/100)
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
Nicasio water systems draw from: Groundwater.
Lead & Copper
- Average lead level (90th percentile): 0.0040 mg/L (EPA action level: 0.015 mg/L)
- 0 ZIP codes exceed the EPA lead action level
Radon Risk
Dominant radon zone: Zone 3 (Low Risk)
Top Contaminants
| Contaminant | Category | Violations | ZIPs Affected |
|---|---|---|---|
| Haloacetic Acids (HAA5) | Disinfection Byproducts | 2 | 1 |
Areas with Most Violations
| ZIP Code | Safety Score | Violations | Health-Based | System |
|---|---|---|---|---|
| 94946 | A | 1 | 1 | NORTH MARIN WATER DISTRICT |
All ZIP Codes in Nicasio
- 94946 [A] — 1 violation ⚠
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.
Nicasio Community Health Snapshot
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
What's in Nicasio's Water?
Based on EPA violation records. Check your ZIP code report for system-specific contaminant data.
Nicasio Infrastructure Age
With 70% 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
The lead that enters tap water in older homes often comes not from the municipal supply but from the home's own plumbing — from solder used in copper joints before the 1986 federal ban, or from lead pipes installed before 1970. In Nicasio, where the median build year is 1973, these older materials are widespread. More than half the residential stock predates the 1986 solder ban, and a significant fraction predates 1970 as well. For residents in those homes, the city-wide water quality picture is a less relevant frame than the specific materials inside their own walls and under their own street.
Over half of homes in Nicasio 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.
How Remediation Costs Compare in Nicasio
Setting Nicasio remediation figures against its property market, the resulting ratio sits comfortably in the low tier — a classification that reflects the kind of household financial position where most homeowners can identify documented issues, schedule the work, and absorb the cost without it registering as a significant budget disruption.
Remediation costs in Nicasio are relatively low compared to home values. The $950–$2,400 estimated range is a small fraction of median property value. Home values are 171% above the California average.
Nicasio: Lead Risk & Vulnerable Populations
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.
Households with kids in the home — for whom CDC guidance places particular weight on minimizing exposure — face a specific local picture in Nicasio. 70% of homes here come from the pre-rule era, and aggregate utility samples either approach or cross 0.015 mg/L. A baseline draw-test kit and certified lead-removal filtration are available via retailer networks for households confirming conditions at a specific tap.
Sources: EPA Lead and Copper Rule, U.S. Census Bureau ACS, CDC childhood lead poisoning prevention guidelines.
Nicasio: Flood History & Water Damage Risk
A moderate NFIP record for Nicasio — 10 insurance claims paired with 100% of ZIP codes in FEMA flood zones — points to a flood history where water-quality pathways have likely been periodically relevant.
Nicasio has a moderate flood history with 10 FEMA claims averaging $3,095 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.
Deep Dive Reports
Detailed analysis for Nicasio, CA