Contra Costa, 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. This is a different measure than the EJ Screening score for this county, which ranks it by percentile against other tracked counties rather than against these fixed caps.
Environmental data for Contra Costa in California · Population: 1,161,458
TRI sites such as Martinez Refining Co LLC; Phillips 66 Rodeo Renewable Energy Complex; Chevron Products Co Richmond Refinery; SDWIS systems such as CONTRA COSTA WATER DISTRICT; CITY OF ANTIOCH; BRENTWOOD; NPL sites such as Concord Naval Weapons Station; Liquid Gold Oil Corp.; United Heckathorn Co. anchor Contra Costa, CA's EPA extract. Derived burden score 83/100 (High Risk) uses fixed national caps on density, log release volume, Superfund count, and health-flagged systems - not an official EPA rating.
EPCRA disclosures in Contra Costa total 15.8M lbs; health-flagged SDWIS rows include BRENTWOOD; WILLOW PARK MARINA; ORWOOD RESORT, while Martinez Refining Co LLC leads TRI pounds. AQS median AQI 48 / peak 94 in 2024.
Largest TRI sites in the extract: Martinez Refining Co LLC; Phillips 66 Rodeo Renewable Energy Complex; Chevron Products Co Richmond Refinery. Named SDWIS systems: CONTRA COSTA WATER DISTRICT; CITY OF ANTIOCH; BRENTWOOD. NPL sites on record: Concord Naval Weapons Station; Liquid Gold Oil Corp.; United Heckathorn Co.. Burden score 83/100 (High Risk) is the only weighted composite here; tables reproduce EPA disclosure history, not a current-safety verdict.
Release-over-release change
What changed for Contra Costa, CA: EPA TRI 2023 reporting year
Same facilities, both years
-3.8%
34 facilities that filed in 2022 and 2023
Whole inventory
-3.8%
2.9 million lb → 2.8 million lb, every facility that filed
Between the two reporting years, 1 facility filed for the first time and 1 stopped filing. Facilities entering or leaving the inventory are excluded from the same-facility comparison above.
- Contra Costa, CA's total reported releases fell from 2.9 million lb in 2022 to 2.8 million lb in 2023, based on EPA TRI filings.
- Contra Costa, CA's land releases rose from 545 lb in 2022 to 2.4 thousand lb in 2023, based on EPA TRI filings.
- Contra Costa, CA's water releases fell from 1.2 million lb in 2022 to 1.1 million lb in 2023, based on EPA TRI filings.
- Contra Costa, CA's off-site transfers rose from 572.3 thousand lb in 2022 to 642.3 thousand lb in 2023, based on EPA TRI filings.
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 | 193 (53%) | 168 | 0 | 94 |
| 2023 | 173 (47%) | 190 | 2 | 110 |
| 2022 | 175 (48%) | 188 | 2 | 129 |
| 2021 | 195 (53%) | 165 | 5 | 150 |
| 2020 | 192 (52%) | 156 | 7 | 221 |
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 (51)
| System | System pop (SDWIS) | Violations |
|---|---|---|
| CONTRA COSTA WATER DISTRICT | 198,000 | 0 |
| CITY OF ANTIOCH | 115,074 | 0 |
| BRENTWOOD | 64,513 | 2 |
| CITY OF PITTSBURG | 62,500 | 0 |
| DIABLO WATER DISTRICT | 43,357 | 0 |
| CITY OF MARTINEZ | 30,997 | 0 |
| TOWN OF DISCOVERY BAY | 16,790 | 0 |
| PLEASANTIMES MUTUAL WATER CO | 644 | 0 |
| CLAYTON PALMS WATER | 549 | 0 |
| WILLOW MOBILE HOME PARK | 481 | 0 |
| WILLOW PARK MARINA | 380 | 31 |
| ORWOOD RESORT | 350 | 1 |
| DELTA MUTUAL WATER COMPANY | 333 | 40 |
| RIVER RANCH MOBILE HOME PARK | 305 | 1 |
| KONOCTI SHORES | 277 | 0 |
| MAPACHE TRAILER PARK | 275 | 0 |
| RIVERVIEW WATER ASSOCIATION | 230 | 0 |
| CAMINO MOBILEHOME | 210 | 0 |
| OAKLEY MUTUAL WATER COMPANY | 170 | 29 |
| BIG OAK MOBILE HOME PARK WATER | 156 | 0 |
| SONOMA RANCH MUTUAL WATER COMPANY | 151 | 1 |
| SHADY REST TRAILER COURT | 150 | 0 |
| GEORGE RANCH MUTUAL WATER COMPANY | 148 | 1 |
| FARRAR PARK PROPERTY OWNERS | 140 | 0 |
| CAMPERS INN - RV & GOLF COURSE | 140 | 0 |
| BETHEL ISLAND MUTUAL WATER CO | 123 | 0 |
| LOCKEFORD MOBILE HOME PARK WTR SYS | 123 | 0 |
| VILLADOM MOBILE HOME PARK | 115 | 11 |
| RUSSOS MOBILE PARK | 110 | 1 |
| GATEWAY MOBILE HOME PARK | 103 | 1 |
| SANDMOUND MUTUAL | 100 | 1 |
| GLENWOOD MOBILE HOME PARK | 100 | 23 |
| DUNROVIN MOBILE HOME VILLAGE | 99 | 0 |
| ANGLERS SUBDIVISION 4 | 99 | 0 |
| BELLA VISTA WATER SYS | 93 | 35 |
| RAPID RIVER MOBILEHOME PARK | 92 | 1 |
| NORTH SIDE MOBILE HOME RANCH | 74 | 2 |
| KNIGHTSEN COMMUNITY WATER SYSTEM | 73 | 0 |
| SANDY POINT MOBILE HOME PARK | 67 | 1 |
| MORAGA HEIGHTS MUTUAL WATER | 66 | 0 |
| ANGLER S RANCH #3 | 60 | 0 |
| MARTIN'S MOBILE HOME COURT | 60 | 29 |
| COUNTRY VILLA APTS | 60 | 49 |
| PINE GROVE MOBILEHOME PARK | 53 | 0 |
| DUTCH SLOUGH WATER WORKS | 49 | 0 |
| CASA MEDANOS WATER SYSTEM | 45 | 0 |
| COLONIA SANTA MARIA | 32 | 1 |
| WILCOX STATION RANCH | 31 | 0 |
| EVERGREEN MOTEL & MHP | 28 | 0 |
| RANDALL-BOLD WATER TREATMENT PLANT | 1 | 0 |
| CCWD/BRENTWOOD WTP | 0 | 0 |
TRI Facilities (42)
Superfund Sites (3)
| Site Name | Status | HRS Score |
|---|---|---|
| Concord Naval Weapons Station | NPL Site | 50.00 |
| Liquid Gold Oil Corp. | Deleted NPL Site | 43.32 |
| United Heckathorn Co. | NPL Site | 38.49 |
Cities in Contra Costa (25)
Frequently Asked Questions
What is the environmental risk level in Contra Costa, California? ▼
Are there Superfund sites in Contra Costa? ▼
How many toxic release facilities are in Contra Costa? ▼
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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.