Mammoth Lakes, CA: 1 Violation — 83/100 (2026)
1 ZIP code · 3 water systems · Updated 2026-06-03
Unlike many cities its size in CA, Mammoth Lakes 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 Mammoth Lakes Compares
Data: EPA SDWIS Last verified: 2026-06-03
Mammoth Lakes Water: The Quick Version
- Your city's water systems recorded 1 violation in the past 5 years.
- Average lead level: 0.0044 mg/L.
- Homes built before 1986: 66% — older plumbing may contain lead solder.
- Estimated remediation: $1,600 per household.
- CDC health risk index: 12.65 — above typical levels.
Water Systems Serving Mammoth Lakes
Across Mammoth Lakes, CA, residential water comes from 3 primary utilities rather than a single consolidated provider. Each system operates independently — managing its own distribution infrastructure, rate schedules, and EPA compliance filings. Federal records track 3 water systems in the area, with these top providers accounting for the majority of residential connections.
Overview
We track water quality and home safety data for 1 ZIP code in Mammoth Lakes, California, covering 3 community water systems serving approximately 8,803 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 Mammoth Lakes: B (83/100)
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
Mammoth Lakes water systems draw from: Groundwater, Surface water.
Lead & Copper
- Average lead level (90th percentile): 0.0044 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 |
|---|---|---|---|
| Haloacetic Acids (HAA5) | Disinfection Byproducts | 2 | 1 |
Areas with Most Violations
| ZIP Code | Safety Score | Violations | Health-Based | System |
|---|---|---|---|---|
| 93546 | B | 1 | 0 | Mammoth Cwd |
All ZIP Codes in Mammoth Lakes
- 93546 [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 Mammoth Lakes
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 Mammoth Lakes
Based on EPA violation records. Check your ZIP code report for system-specific contaminant data.
How Old Is Mammoth Lakes's Housing Stock?
With 66% 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
Plumbing risk in older housing is defined by two eras: the pre-1970 period when lead pipes were commonly used for service lines, and the 1970-to-1986 period when lead solder remained standard in copper plumbing until the federal ban. Mammoth Lakes's median build year of 1971 lands in a range where both eras are heavily represented in the housing stock. That creates an elevated aggregate environment for plumbing-related lead exposure — one that city-level water quality averages don't capture, because the risk sits inside individual properties rather than in the distribution system.
Over half of homes in Mammoth Lakes 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.
Mammoth Lakes: Remediation Cost in Perspective
At current valuations, Mammoth Lakes sits in the low remediation-share tier — the equity impact of fixing documented issues is proportionally minor.
Remediation costs in Mammoth Lakes are relatively low compared to home values. The $800–$2,600 estimated range is a small fraction of median property value. Home values are 16% below the California average.
Protecting Children from Lead in Mammoth Lakes
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.
In recent monitoring under the Lead and Copper Rule, citywide samples for Mammoth Lakes have approached or crossed the regulatory action level on multiple occasions. Combined with 66% of stock dating from the pre-rule era, the picture supports baseline single-tap reads as a standard household-level step.
Sources: EPA Lead and Copper Rule, U.S. Census Bureau ACS, CDC childhood lead poisoning prevention guidelines.
Climate-Related Water Risk for Mammoth Lakes
How does Mammoth Lakes's flood record connect to local water quality? The NFIP documents 3 claims — enough to signal recurring events — and 100% of ZIP codes carry FEMA flood zone status. That combination places flooding in the category of factors that can periodically affect water infrastructure, even if the area isn't among the highest-exposure communities in the NFIP dataset.
Mammoth Lakes has a moderate flood history with 3 FEMA claims averaging $15,353 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>$1,600</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 Mammoth Lakes, CA