Mariposa, CA: 1 Violation — 81/100 (2026)
1 ZIP code · 5 water systems · Updated 2026-06-03
The water systems supplying Mariposa show a track record of above-average compliance with federal standards — consistently among the better performers in CA.
How Mariposa Compares
Data: EPA SDWIS Last verified: 2026-06-03
Mariposa Water: The Quick Version
- Your city's water systems recorded 1 violation in the past 5 years.
- Average lead level: 0.0025 mg/L.
- Homes built before 1986: 54% — older plumbing may contain lead solder.
- Estimated remediation: $400 per household.
- CDC health risk index: 14 — above typical levels.
Water Systems Serving Mariposa
Residential addresses in Mariposa, CA are served by 3 primary water providers out of 5 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 1 ZIP code in Mariposa, California, covering 5 community water systems serving approximately 10,164 people.
1 of 1 ZIP code (100%) have recorded EPA violations. All violations are monitoring/reporting type.
Home Safety Score
Average Home Safety Score for Mariposa: B (81/100)
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
Mariposa water systems draw from: Groundwater, Surface water.
Lead & Copper
- Average lead level (90th percentile): 0.0025 mg/L (EPA action level: 0.015 mg/L)
- 0 ZIP codes exceed the EPA lead action level
Radon Risk
Dominant radon zone: Zone 2 (Moderate Risk)
The EPA recommends testing homes in Zone 1 and Zone 2 areas for radon.
Top Contaminants
| Contaminant | Category | Violations | ZIPs Affected |
|---|---|---|---|
| Stage 1 DBP Rule | Treatment Technique | 2 | 1 |
Areas with Most Violations
| ZIP Code | Safety Score | Violations | Health-Based | System |
|---|---|---|---|---|
| 95338 | B | 1 | 0 | Mariposa Public Utility District |
All ZIP Codes in Mariposa
- 95338 [B] — 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.
CDC Health Data for Mariposa
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 Mariposa
Based on EPA violation records. Check your ZIP code report for system-specific contaminant data.
How Old Is Mariposa's Housing Stock?
With 54% 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
For residents trying to assess tap water risk in Mariposa, the median build year of 1985 is the starting context. It signals that a majority of homes were constructed before 1986 — the year federal rules prohibited lead solder in new plumbing — and that a significant share likely predates 1970, when lead pipes were still a common choice for residential service connections. Neither risk tier is rare in this housing inventory.
Over half of homes in Mariposa 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.
Mariposa: Remediation Cost in Perspective
Low proportionality — that's the Mariposa picture when remediation costs are placed against typical home equity.
Remediation costs in Mariposa are relatively low compared to home values. The $0–$800 estimated range is a small fraction of median property value. Home values are 50% below the California average.
Protecting Children from Lead in Mariposa
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.
Before the federal solder ban, lead solder was a routine plumbing material, and 54% of the Mariposa inventory was built in that earlier era — a share large enough to move household-level reads onto the standard list.
Sources: EPA Lead and Copper Rule, U.S. Census Bureau ACS, CDC childhood lead poisoning prevention guidelines.
Deep Dive Reports
Detailed analysis for Mariposa, CA