Contaminant 5000
Unresolved Phase I/II/V Inorganic Chemical Rules violation cited in 2024 (contaminant 5000).
City · TRI 2024
Mariposa, California Pollution
0 TRI facilities inside the city limits and 5 public water systems serving residents.
FIPS 0645932 · population 1,060 · Mariposa County
Anomaly engine
Notable Signals
Contaminant 5200
Unresolved Phase I/II/V Inorganic Chemical Rules violation cited in 2024 (contaminant 5200).
Contaminant 5200
Unresolved Phase I/II/V Inorganic Chemical Rules violation cited in 2024 (contaminant 5200).
Contaminant 5000
Unresolved Phase I/II/V Inorganic Chemical Rules violation cited in 2025 (contaminant 5000).
Pollutant pathways
Mariposa Pollutant Multi-Year Trends
Ozone 8-hour 4th-highest daily max (NAAQS 0.070 ppm (8-hour))Health riskGround-level ozone (smog) forms when vehicle and industrial emissions react in sunlight. Inflames the airways, triggers asthma attacks, and worsens heart and lung disease.
Ozone 8-hour 4th-highest daily max (NAAQS 0.070 ppm (8-hour)) concentrations have fallen 22% since 2010.
Lifetime cancer risk all pollutants (100 in a million (EPA elevated threshold))Health riskEPA-modeled added cancer cases per million residents from a lifetime of breathing local air toxics. EPA flags 100-in-a-million as elevated.
Single-vintage exposure modeling — EPA cadence is multi-year, so no trend line yet.
Formaldehyde ambient mean (0.077 µg/m³ (1-in-a-million URE))Health riskAn air toxic emitted by refineries, wood products, and combustion. EPA classifies it as a known human carcinogen — long-term inhalation raises cancer risk.
Single-vintage exposure modeling — EPA cadence is multi-year, so no trend line yet.
Benzene ambient mean (0.13 µg/m³ (1-in-a-million URE))Health riskAn air toxic from gasoline, refineries, and tobacco smoke. A known human carcinogen — chronic exposure is linked to leukemia and other blood cancers.
Single-vintage exposure modeling — EPA cadence is multi-year, so no trend line yet.
TRI air releases (5.1 fugitive + 5.2 stack)Health riskToxic chemicals reported by industrial facilities as released into the air — fugitive leaks plus smokestack emissions. Higher pounds means more inhaled exposure for nearby residents.
Single-vintage exposure modeling — EPA cadence is multi-year, so no trend line yet.
TRI water releases (5.3)Health riskToxic chemicals reported by industrial facilities as discharged to surface waters (rivers, lakes, the ocean). Affects fishing, recreation, and downstream drinking-water intakes.
Single-vintage exposure modeling — EPA cadence is multi-year, so no trend line yet.
TRI land + off-site releasesHealth riskToxic chemicals released to land on-site or transferred off-site for disposal — landfills, deep-well injection, and similar. Risks groundwater contamination over time.
Single-vintage exposure modeling — EPA cadence is multi-year, so no trend line yet.
Drinking water · SDWIS
Water Systems Serving Mariposa
4 unresolved violations on the SDWIS record across utilities serving this city.
5
Utilities serving
3,695
Population served
1
Health-based · 5yr
4
Unresolved
| Water system | PWSID | Population served | Health-based · 5yr | Status |
|---|---|---|---|---|
| Mariposa Pines Mutual Private | CA2210906 | 284 | 1 | UNRESOLVED |
| Ponderosa Basin Mutual Wtr Co Private | CA2210002 | 798 | 0 | UNRESOLVED |
| Yosemite West Water System Municipal | CA2210924 | 420 | 0 | UNRESOLVED |
Showing the 3 systems with recorded health-based or unresolved violations. 2 additional systems are in compliance with no recorded health-based violations in the past 5 years and are not individually tabulated.
A public water systemis the regulated entity, not the city. EPA's SDWIS definition covers anything serving 25+ people for 60+ days a year or with 15+ service connections — that includes municipal utilities (City of Stockton), water districts, mobile home parks operating their own wells, schools, and small private subdivisions. Each system is independently monitored. Some systems serve multiple cities; some cities are served by many systems.
Equity context · ACS 2018-2022 · USEPA-clone EJ disparity
Who Lives In Mariposa
Mariposa, California (Census place block groups): 1,060 residents. Why we surface this →
24.3%
Low-income
19.3%
People of color
8.3%
Under age 5
40.5%
Over age 64
Source: Census ACS 2018-2022 (5-year) + USEPA-clone EJ blockgroup stats (raw indicators + EJ disparity mirror).
Health context
Co-Located Health Indicators
Modeled adult-prevalence estimates published by CDC PLACES, paired with this city's pollution and demographic context. Comparisons are ecological, not causal — pollution and disease prevalence covary at the area level, but the data does not attribute any individual's diagnosis to local exposure. How this section works →
Adult asthma (current)
10.7%
CDC PLACES · 2025 release · BRFSS 2022-2023
COPD prevalence
8.6%
CDC PLACES · 2025 release · BRFSS 2022-2023
Coronary heart disease
9.0%
CDC PLACES · 2025 release · BRFSS 2022-2023
Diabetes (diagnosed)
13.4%
CDC PLACES · 2025 release · BRFSS 2022-2023
Frequent mental distress
16.6%
CDC PLACES · 2025 release · BRFSS 2022-2023
PLACES uses BRFSS-modeled small-area estimates, not individual records. Crude prevalence shown above is the local rate as published; comparators are age-adjusted vs the California mean and the US mean — both population-weighted across counties — so geographies with different age structures stay apples-to-apples. Sources: CDC PLACES · 2025 release · BRFSS 2022-2023.
Sources.
- EPA Toxics Release Inventory · retrieved 2026-05-07.
- EPA Safe Drinking Water Information System · retrieved 2026-05-07.