San Luis Obispo, 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 San Luis Obispo in California · Population: 281,486
TRI sites such as U.S. Army National Guard Camp Roberts Ranges; Joslyn Sunbank Co LLC; Phillips 66 Co-Santa Maria Refinery; SDWIS systems such as SAN LUIS OBISPO WATER DEPARTMENT; CITY OF PASO ROBLES WATER DIVISION; ATASCADERO MUTUAL WATER CO; NPL sites such as Klau/Buena Vista Mine anchor San Luis Obispo, CA's EPA extract. Derived burden score 49/100 (Moderate 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 San Luis Obispo include CALIFORNIA MENS COLONY; PISMO BEACH WATER DEPARTMENT; CAMBRIA COMM SERVICES DIST, while U.S. Army National Guard Camp Roberts Ranges leads reported TRI pounds among local Form R filers. AQS median AQI 49 / peak 122 in 2024.
Burden score 49/100 (Moderate 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 San Luis Obispo -- 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.
Release-over-release change
What changed for San Luis Obispo, CA: EPA TRI 2023 reporting year
Same facilities, both years
-60.0%
10 facilities that filed in 2022 and 2023
Whole inventory
-60.0%
55.5 thousand lb → 22.2 thousand lb, every facility that filed
Between the two reporting years, 1 facility filed for the first time and 3 stopped filing. Facilities entering or leaving the inventory are excluded from the same-facility comparison above.
- San Luis Obispo, CA's total reported releases fell from 55.5 thousand lb in 2022 to 22.2 thousand lb in 2023, based on EPA TRI filings.
- San Luis Obispo, CA's air releases fell from 10.5 thousand lb in 2022 to 2.1 thousand lb in 2023, based on EPA TRI filings.
- San Luis Obispo, CA's land releases fell from 24.4 thousand lb in 2022 to 7.4 thousand lb in 2023, based on EPA TRI filings.
- San Luis Obispo, CA's water releases fell from 126 lb in 2022 to 71 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%) | 163 | 10 | 122 |
| 2023 | 207 (57%) | 152 | 6 | 122 |
| 2022 | 117 (32%) | 245 | 3 | 115 |
| 2021 | 154 (42%) | 203 | 8 | 133 |
| 2020 | 161 (44%) | 174 | 21 | 334 |
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 (61)
| System | System pop (SDWIS) | Violations |
|---|---|---|
| SAN LUIS OBISPO WATER DEPARTMENT | 47,788 | 0 |
| CITY OF PASO ROBLES WATER DIVISION | 31,176 | 0 |
| ATASCADERO MUTUAL WATER CO | 30,618 | 0 |
| CITY OF ARROYO GRANDE UTILITIES DIVISION | 17,963 | 0 |
| CALIFORNIA MENS COLONY | 15,000 | 1 |
| NIPOMO COMM SERVICES DIST | 13,771 | 0 |
| MORRO BAY PW DEPT - WATER DIVISION | 13,757 | 0 |
| CITY OF GROVER BEACH PUBLIC WORKS DEPT | 12,701 | 0 |
| PISMO BEACH WATER DEPARTMENT | 8,036 | 10 |
| TEMPLETON CSD | 8,011 | 0 |
| OCEANO COMM SERVICES DIST. | 7,601 | 0 |
| LOS OSOS COMMUNITY SERVICES DISTRICT | 7,086 | 0 |
| CAMBRIA COMM SERVICES DIST | 5,532 | 7 |
| HERITAGE RANCH CSD | 2,956 | 57 |
| CAYUCOS BEACH MUTUAL WATER COMPANY | 2,567 | 0 |
| MORRO ROCK MUTUAL WATER CO | 2,181 | 0 |
| AVILA BEACH COMMUNITY SERVICES DISTRICT | 1,630 | 0 |
| SAN MIGUELITO MWC | 1,600 | 5 |
| LOPEZ PROJECT | 1,569 | 2 |
| SLO CWWD NO. 23 - SANTA MARGARITA | 1,291 | 0 |
| SLOCSA #10A - CAYUCOS | 1,200 | 0 |
| SLO CSA NO. 16 - SHANDON | 1,085 | 0 |
| LAUREATE WATER COMPANY | 700 | 0 |
| PRESERVE AT MILLERTON LAKE WATER SYSTEM | 600 | 0 |
| MESA DUNES MOBILE HOME ESTATES | 600 | 0 |
| S & T MUTUAL WATER COMPANY | 591 | 0 |
| WOODLAND PARK MUTUAL WATER CO | 538 | 29 |
| WALNUT HILLS MUTUAL WATER CO | 486 | 0 |
| SAN SIMEON CSD | 462 | 8 |
| GARDEN FARMS C.W.D. | 440 | 0 |
| LOS ROBLES MOBILE HOME ESTATES | 420 | 0 |
| GREEN RIVER MUTUAL WATER CO. | 350 | 2 |
| SANTA YSABEL RANCH MWC | 344 | 0 |
| RANCHO COLINA MOBILE HOME PARK | 252 | 3 |
| SNAKE RIVER RESORT | 150 | 0 |
| GRAN CIELO MUTUAL WATER COMPANY | 139 | 0 |
| IRISH HILLS MUTUAL WATER CO | 135 | 0 |
| CANYON CREST MUTUAL BENEFIT WC | 133 | 0 |
| CALLENDER GROVE MUTUAL WATER | 126 | 0 |
| SPANISH LAKES MUTUAL WATER CO | 125 | 0 |
| HALCYON WATER SYSTEM | 110 | 1 |
| LAS VENTANAS RANCH | 108 | 0 |
| VARIAN RANCH MUTUAL WATER | 105 | 0 |
| RESTHAVEN MOBILE HOME PARK | 99 | 33 |
| AFUERA DE CHORRO WATER COMPANY | 85 | 0 |
| KEN MAR GARDENS | 84 | 36 |
| BARON CANYON MUTUAL WATER CO. | 81 | 0 |
| LAGUNA NEGRA MUTUAL WATER CO. | 80 | 0 |
| AVILA VALLEY MUTUAL WATER CO | 75 | 0 |
| H2O, INC | 70 | 0 |
| MONTE SERENO MUTUAL BENEFIT WATER | 65 | 0 |
| RANCHO SALINAS MBWC | 50 | 0 |
| RANCHO NIPOMO WATER COMPANY | 44 | 0 |
| ALMIRA WATER ASSOCIATION | 40 | 37 |
| TERRA DE ORO WATER COMPANY | 38 | 0 |
| HIGUERA APARTMENTS | 30 | 34 |
| MUSTANG SPRINGS MUTUAL WATER | 30 | 9 |
| ADA'S LODGES | 25 | 0 |
| SLO CSA NO. 10 - CAYUCOS WTP | 0 | 0 |
| CHORRO VALLEY PIPELINE - SLO COUNTY | 0 | 0 |
| NACIMIENTO WATER PROJECT | 0 | 0 |
TRI Facilities (15)
| # | Facility | Total Releases |
|---|---|---|
| 1 | U.S. Army National Guard Camp Roberts Ranges | 115.2K lbs |
| 2 | Joslyn Sunbank Co LLC | 86.1K lbs |
| 3 | Phillips 66 Co-Santa Maria Refinery | 39.2K lbs |
| 4 | U.S. Army National Guard Camp San Luis Obispo Ranges | 31.9K lbs |
| 5 | Promega Corp | 10.1K lbs |
| 6 | Entegris - San Luis Obispo | 2.0K lbs |
| 7 | Rantec Power Systems Inc | 1.2K lbs |
| 8 | Coast Southwest Surfactants LLC | 43 lbs |
| 9 | Hanson Aggregates Mid-Pacific Inc | 0 lbs |
| 10 | Martin Marietta Ca Ready Mix - San Luis Obipso | 0 lbs |
| 11 | Martin Marietta California Ready-Mix LLC - Nipomo Ready Mix | 0 lbs |
| 12 | Calportland Co San Luis Obispo | 0 lbs |
| 13 | Zurn Water LLC | 0 lbs |
| 14 | Calportland Co Paso Robles Plant | 0 lbs |
| 15 | Firestone Walker LLC | 0 lbs |
Superfund Sites (1)
| Site Name | Status | HRS Score |
|---|---|---|
| Klau/Buena Vista Mine | NPL Site | 50.00 |
Cities in San Luis Obispo (15)
Frequently Asked Questions
What is the environmental risk level in San Luis Obispo, California? ▼
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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.