Yosemite National Park, CA Water Safety: 53/100 (2026)
1 ZIP code · 1 water system · Updated 2026-06-04
Systems across Yosemite National Park show elevated violation counts against CA benchmarks — the low safety grade reflects that ongoing compliance pattern.
How Yosemite National Park Compares
Data: EPA SDWIS Last verified: 2026-06-04
What You Should Know About Yosemite National Park Water
- Homes built before 1986: 72% — older plumbing may contain lead solder.
- Estimated remediation: $400 per household.
- CDC health risk index: 14 — above typical levels.
Who Supplies Your Water in Yosemite National Park
Supply infrastructure in Yosemite National Park, CA runs through a single dominant provider — the main entity among 1 tracked system through which rate decisions, infrastructure work, and federal compliance are managed.
Overview
We track water quality and home safety data for 1 ZIP code in Yosemite National Park, California, covering 1 community water system serving approximately 2,067 people.
No EPA violations recorded across any ZIP codes in Yosemite National Park — an excellent indicator of water quality.
Home Safety Score
Average Home Safety Score for Yosemite National Park: D (53/100)
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
Yosemite National Park water systems draw from: Surface water.
Lead & Copper
- Lead data: not yet available for Yosemite National Park
- 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.
Areas with No Violations
| ZIP Code | Safety Score | System | Population |
|---|---|---|---|
| 95389 | D | MARIPOSA PUBLIC UTILITY DIST | 2,000 |
All ZIP Codes in Yosemite National Park
- 95389 [D]
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 Yosemite National Park
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
Housing & Infrastructure in Yosemite National Park
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
Housing age is one of the most reliable proxies for plumbing-era lead risk, because two federal milestones — the widespread use of lead pipes before 1970 and the continued use of lead solder until 1986 — define the highest-risk tiers of the residential housing stock. With a median build year of 1977, Yosemite National Park falls squarely within the older range — meaning a large fraction of the housing was built under the plumbing standards of those earlier eras. The distribution above captures where that risk concentrates, and why older neighborhoods warrant particular attention from residents concerned about tap water quality.
Over half of homes in Yosemite National Park 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.
Cost Context: What Remediation Means for Yosemite National Park Homeowners
Because property values in Yosemite National Park comfortably exceed estimated remediation costs, the equity impact here is proportionally small.
Remediation costs in Yosemite National Park are relatively low compared to home values. The $0–$800 estimated range is a small fraction of median property value. Home values are 24% above the California average.
Lead Exposure Risk for Children in Yosemite National Park
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 shapes the local picture: 72% of Yosemite National Park homes predate the federal solder ban, and aggregate sampling either approaches or crosses the action benchmark. That mix makes a single-home draw a standard pre-purchase or pre-occupancy step.
Sources: EPA Lead and Copper Rule, U.S. Census Bureau ACS, CDC childhood lead poisoning prevention guidelines.
What You Can Do in Yosemite National Park
- 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. With 72% of homes built before 1986, lead solder is a real possibility.
- Review your water system's CCR. Your utility publishes an annual Consumer Confidence Report with detailed test results. Request it or find it online.
Deep Dive Reports
Detailed analysis for Yosemite National Park, CA