Napa, CA: Lead Above EPA Limits — 57/100 (2026)
3 ZIP codes · 7 water systems · Updated 2026-06-03
In recent monitoring cycles, Napa tap water shows a mixed record for CA — several systems have documented violations alongside areas with clean compliance histories.
How Napa Compares
Data: EPA SDWIS Last verified: 2026-06-03
Napa Water: The Quick Version
- Your city's water systems recorded 3 violations in the past 5 years.
- Average lead level: 0.1025 mg/L — exceeds the EPA action level of 0.015 mg/L.
- Homes built before 1986: 72% — older plumbing may contain lead solder.
- Estimated remediation: $6,090 per household.
- CDC health risk index: 11.55.
Water Systems Serving Napa
Residential addresses in Napa, CA are served by 3 primary water providers out of 7 systems in federal records. Each system maintains separate infrastructure and files its own EPA compliance reports, so service conditions are not uniform across the city.
Overview
We track water quality and home safety data for 3 ZIP codes in Napa, California, covering 7 community water systems serving approximately 92,380 people.
3 of 3 ZIP codes (100%) have recorded EPA violations. All violations are monitoring/reporting type.
Home Safety Score
Average Home Safety Score for Napa: C (57/100)
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
Napa water systems draw from: Groundwater, Surface water.
Lead & Copper
- Average lead level (90th percentile): 0.1025 mg/L (exceeds EPA action level) (EPA action level: 0.015 mg/L)
- 3 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): 3 ZIP codes
Top Contaminants
| Contaminant | Category | Violations | ZIPs Affected |
|---|---|---|---|
| Consumer Confidence Report Rule | Reporting | 4 | 3 |
Areas with Most Violations
| ZIP Code | Safety Score | Violations | Health-Based | System |
|---|---|---|---|---|
| 94558 | D | 1 | 0 | City of Napa, |
| 94559 | D | 1 | 0 | City of Napa, |
| 94581 | C | 1 | 0 | City of Napa, |
All ZIP Codes in Napa
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 Napa
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
Key Contaminants Detected in Napa
Based on EPA violation records. Check your ZIP code report for system-specific contaminant data.
How Old Is Napa's Housing Stock?
With 72% 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
Napa's housing stock is predominantly older, with a median build year of 1969 that reflects decades of construction before federal plumbing standards were tightened. The 1986 ban on lead solder and the pre-1970 era of lead service lines are both relevant benchmarks here — a significant share of the residential inventory predates one or both of those cutoffs, creating an elevated baseline for plumbing-related lead risk that aggregate water quality data may not fully reflect at the household level.
Over half of homes in Napa 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.
Napa: Remediation Cost in Perspective
Setting Napa 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 Napa are relatively low compared to home values. The $4,060–$8,220 estimated range is a small fraction of median property value. Home values are 19% above the California average.
Protecting Children from Lead in Napa
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.
Older interior plumbing dominates the Napa inventory at 72%, and citywide utility samples have crossed the federal action mark. Two independent indicators align here, raising lead to a household-level priority — particularly for families with kids.
<strong>3 ZIP codes</strong> (100% of the city) exceed the EPA lead action level of 0.015 mg/L.
Sources: EPA Lead and Copper Rule, U.S. Census Bureau ACS, CDC childhood lead poisoning prevention guidelines.
Climate-Related Water Risk for Napa
Because Napa's NFIP claim count reaches 1159 and 67% of ZIP codes fall within FEMA-designated flood zones, flood exposure here operates differently than it does in lower-claim communities. In areas with isolated flood events, water-quality infrastructure can typically absorb the stress and recover between events. In communities with repeated high-volume flooding, treatment plants face recurring overload conditions, private wells in FEMA-designated zones accumulate repeated infiltration episodes, and distribution systems experience repeated pressure events that can drive backflow. The claim record for this area points to that second category: a flood environment where water infrastructure stress is periodic and documented, not theoretical.
Napa has a significant flood history with 1,159 FEMA flood insurance claims on record, averaging $22,847 per claim. With 67% of ZIP codes in FEMA-designated flood zones, flood risk is a major concern for homeowners and water quality.
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>$6,090</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 Napa
- Test your water at home. City-level data shows averages — your tap may differ. Lead testing is especially recommended given the area's lead levels.
- Install a certified water filter. Filters rated for Consumer Confidence Report Rule can reduce the most common contaminant found in Napa's water.
- Check your home's plumbing. With 72% of homes built before 1986, lead solder is a real possibility.
Deep Dive Reports
Detailed analysis for Napa, CA