Tuolumne, CA
Transparent derived index from EPA TRI / SDWIS / Superfund extracts: not an official EPA rating. Fixed caps: facilities ≤25 pts (50+ = max), log10 releases ≤25 pts, Superfund ≤25 pts (5/site), health-violation systems ≤15 pts (3/system), high-chemical facilities ≤10 pts. Bands: High ≥60, Moderate ≥30. See methodology.
Environmental data for Tuolumne in California · Population: 54,873
TRI sites such as Spi Sonora Div; SDWIS systems such as TUD - UPPER BASIN WATER SYSTEM; TUD - SONORA/JAMESTOWN WATER SYSTEM; TUD - COLUMBIA WATER SYSTEM anchor Tuolumne, CA's EPA extract. Derived burden score 16/100 (Low Risk) uses fixed national caps on density, log release volume, Superfund count, and health-flagged systems - not an official EPA rating.
Health-flagged SDWIS rows in Tuolumne include CDCR - SIERRA CONSERVATION CENTER; GROVELAND COMMUNITY SERV DIST; LAKE DON PEDRO CSD, while Spi Sonora Div leads reported TRI pounds among local Form R filers. AQS median AQI 40 / peak 115 in 2024.
Burden score 16/100 (Low Risk) is the only weighted composite on this page. The tables below list every TRI facility, SDWIS system, and Superfund site EPA has on record for Tuolumne -- not just the names called out above -- reproducing the disclosure history as filed, not a current-safety verdict. Extract current as of 2026-08-25.
Air Quality History (2020–2024)
EPA Air Quality Index (AQI) data showing how many days per year fall into each air quality category.
| Year | Good | Moderate | Unhealthy (SG) | Max AQI |
|---|---|---|---|---|
| 2024 | 286 (81%) | 64 | 4 | 115 |
| 2023 | 237 (82%) | 51 | 2 | 112 |
| 2022 | 237 (95%) | 12 | 1 | 108 |
| 2021 | 295 (82%) | 63 | 2 | 136 |
| 2020 | 277 (78%) | 71 | 5 | 143 |
Source: EPA Air Quality System (AQS) Annual AQI by County AQI categories: Good (0-50), Moderate (51-100), Unhealthy for Sensitive Groups (101-150), Unhealthy (151-200), Very Unhealthy (201-300), Hazardous (301+)
For real-time air quality readings and pollutant breakdowns in California, see the EPA's AirNow.gov.
Water Systems (37)
| System | System pop (SDWIS) | Violations |
|---|---|---|
| TUD - UPPER BASIN WATER SYSTEM | 13,280 | 0 |
| TUD - SONORA/JAMESTOWN WATER SYSTEM | 11,054 | 0 |
| TUD - COLUMBIA WATER SYSTEM | 5,463 | 0 |
| CDCR - SIERRA CONSERVATION CENTER | 3,571 | 8 |
| GROVELAND COMMUNITY SERV DIST | 3,400 | 3 |
| LAKE DON PEDRO CSD | 3,240 | 1 |
| TWAIN HARTE COMMUNITY SERVICES DISTRICT | 2,378 | 0 |
| MI WUK VILLAGE MUT WTR CO | 2,163 | 0 |
| COLD SPRINGS WATER CO | 1,771 | 0 |
| TUD - PONDEROSA | 1,767 | 0 |
| TUD - TUOLUMNE WATER SYSTEM | 1,761 | 0 |
| PINECREST PERMITTEES ASSN | 1,298 | 1 |
| PHOENIX LAKE ESTATES CC MWC | 1,168 | 0 |
| SONORA MEADOWS MUTUAL WTR CO | 1,123 | 2 |
| DON PEDRO REC AG:FLEM.MEADOWS | 1,041 | 0 |
| TUD-APPLE VALLEY ESTATES | 826 | 0 |
| BELLEVIEW OAKS MUTUAL WATER CO | 468 | 0 |
| MI WUK HEIGHTS MWC | 445 | 0 |
| SLIDE INN SNOWBOWL WATER CO | 417 | 0 |
| SIERRA PARK WATER COMPANY INC. | 400 | 4 |
| SIERRA VILLAGE MUTUAL WATER CO | 361 | 0 |
| LEISURE PINES MUTUAL WATER CO | 340 | 1 |
| RAWHIDE MUTUAL WATER COMPANY | 269 | 0 |
| SUGAR PINE RV RESORT | 219 | 0 |
| GOLDEN SIERRA ESTATES_FKA MOTHER LODE | 210 | 0 |
| TWAIN HARTE VALLEY MWC | 202 | 1 |
| ALPINE ACRES MUTUAL WATER CO | 195 | 1 |
| MULLER MUTUAL WATER COMPANY | 154 | 0 |
| CAL FIRE BASELINE CONSERVATION CAMP | 150 | 7 |
| SIERRA TWAIN HARTE MHP | 129 | 0 |
| 49ER TRAILER RANCH | 115 | 0 |
| LONG BARN PROPERTY OWNERS | 97 | 0 |
| TUD-PEACEFUL PINES WATER SYSTEM | 92 | 0 |
| YOSEMITE VISTA ESTATES | 85 | 0 |
| TUD-WARDS FERRY RANCHES | 62 | 1 |
| Tuolumne Me-Wuk Ridgeline | 30 | 0 |
| SIERRA VILLAGE MOBILE HOME PARK | 22 | 1 |
TRI Facilities (1)
| # | Facility | Total Releases |
|---|---|---|
| 1 | Spi Sonora Div | 1 lbs |
Cities in Tuolumne (12)
Frequently Asked Questions
What is the environmental risk level in Tuolumne, California? ▼
Are there Superfund sites in Tuolumne? ▼
How many toxic release facilities are in Tuolumne? ▼
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Is the drinking water safe in Tuolumne? ▼
What environmental agencies cover Tuolumne? ▼
What does this county environmental profile show?
This county environmental profile rolls up EPA Toxics Release Inventory facility reports, Safe Drinking Water Information System public-water-system filings, and Superfund National Priorities List sites for the county boundary defined by the U.S. Census Bureau. Facility counts reflect facilities with a reporting address inside the county, not where downstream environmental effects may be observed. Population figures are from the most recent Census ACS 5-year estimate. The county detail page is updated whenever the upstream EPA programs publish revised data; see the methodology page for the documented ingest cadence and the editorial choices governing how aggregations are computed.
Read our methodology - how this data is sourced, computed, and verified.