Custer, SD
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 Custer in South Dakota · Population: 8,686
SDWIS systems such as CUSTER; HERMOSA WATER USERS ASSOCIATION; FAIRBURN WATER ASSOCIATION anchor Custer, SD's EPA extract. Derived burden score 9/100 (Low Risk) uses fixed national caps on density, log release volume, Superfund count, and health-flagged systems - not an official EPA rating.
No TRI Form R facilities sit in Custer in this extract; water coverage still lists CUSTER; HERMOSA WATER USERS ASSOCIATION; FAIRBURN WATER ASSOCIATION. AQS monitors logged median AQI 44 / peak 126 in 2024.
Burden score 9/100 (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 Custer -- 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 | 276 (75%) | 81 | 9 | 126 |
| 2023 | 308 (84%) | 48 | 4 | 167 |
| 2022 | 298 (82%) | 62 | 2 | 130 |
| 2021 | 302 (83%) | 59 | 2 | 209 |
| 2020 | 323 (88%) | 41 | 2 | 119 |
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 South Dakota, see the EPA's AirNow.gov.
Water Systems (4)
| System | System pop (SDWIS) | Violations |
|---|---|---|
| CUSTER | 1,919 | 0 |
| HERMOSA WATER USERS ASSOCIATION | 108 | 2 |
| FAIRBURN WATER ASSOCIATION | 65 | 4 |
| NORTH HERMOSA WUD | 40 | 1 |
Cities in Custer (3)
Frequently Asked Questions
What is the environmental risk level in Custer, South Dakota? ▼
Are there Superfund sites in Custer? ▼
How many toxic release facilities are in Custer? ▼
What is the air quality in Custer? ▼
Is the drinking water safe in Custer? ▼
What environmental agencies cover Custer? ▼
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.