Lewis And Clark, MT
A PlainEnviro-computed score from reported facility/violation counts, not an official EPA rating, health forecast, or population-adjusted rate. See methodology.
Environmental data for Lewis And Clark in Montana · Population: 72,580
Lewis And Clark, MT is tracked across three EPA datasets covering 5 Toxics Release Inventory (TRI) facilities, 49 Safe Drinking Water Act systems, and 0 Superfund National Priorities List sites. Together these generate an environmental burden score of 34/100 (Moderate Risk), calibrated against national distributions for facility density, chemical release volume, Superfund concentration, and water-system health violations.
Industrial disclosures inside the county total 146.3K lbs of reported toxic releases under EPCRA Section 313, while 14 water systems carry an active health-based violation in the SDWIS record. EPA Air Quality System monitors logged a median AQI of 46 and a peak AQI of 160 in 2024, with 64% of observed days rated "Good" (0–50).
All figures below draw directly from federal EPA records, TRI self-reported emissions, SDWIS compliance history, NPL Hazard Ranking System scores, and AQS daily AQI summaries, and are not adjusted, weighted, or forecast. A past violation or elevated score does not itself indicate current unsafe conditions; it documents the regulatory and disclosure history publicly filed with the U.S. Environmental Protection Agency through the most recent reporting cycle.
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 | 233 (64%) | 127 | 5 | 160 |
| 2023 | 240 (66%) | 120 | 3 | 165 |
| 2022 | 239 (65%) | 119 | 4 | 167 |
| 2021 | 249 (68%) | 99 | 14 | 156 |
| 2020 | 277 (76%) | 84 | 1 | 168 |
Source: EPA Air Quality System (AQS) Annual AQI by County 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 Montana, see the EPA's AirNow.gov.
Water Systems (49)
| System | Population | Violations |
|---|---|---|
| HELENA WATER SYSTEM | 32,091 | 12 |
| EAST HELENA CITY OF | 2,114 | 1 |
| EASTGATE VILLAGE SEWER AND WATER | 2,000 | 0 |
| VA MEDICAL CENTER HELENA | 1,275 | 0 |
| HELENA LEISURE LLC | 1,200 | 0 |
| JEFFERSON HILLS WUA | 780 | 2 |
| NORTH STAR PUD | 715 | 0 |
| WINDSOR ESTATES | 530 | 0 |
| COVERED WAGON MB HM PARK | 500 | 0 |
| LA CASA GRANDE WATER AND SEWER DISTRICT | 404 | 0 |
| SKYVIEW WATER AND SEWER UTILITY | 400 | 3 |
| GOLDEN ESTATES HOMEOWNERS ASSOCIATION | 400 | 0 |
| MOUNTAIN ACRES MB HM PK | 320 | 0 |
| RIDGEWOOD TERRACE MHP | 280 | 0 |
| GRASS LAND ESTATES | 228 | 0 |
| HOLMBERG VILLAGE ESTATES | 225 | 1 |
| GLACIER POINT HO AND WUA | 210 | 1 |
| BRIDGE CREEK ESTATES SUBDIVISION | 205 | 0 |
| PELE PARK | 186 | 0 |
| DAVIS MEADOW VILLAGE | 180 | 0 |
| TOWN VIEW ESTATES WUA INC | 175 | 0 |
| MOUNTAIN HERITAGE WATER SYSTEM | 175 | 0 |
| PRAIRIE MOBILE VILLAGE | 163 | 0 |
| PEBBLE GARDENS MOBILE HOME CT | 125 | 0 |
| HOMESTEAD VALLEY WUA HVHA | 105 | 0 |
| BRYANT NO 3 SUBDIVISION | 100 | 0 |
| NORTH FORESTVALE HOMEOWNERS | 98 | 0 |
| CAMEL MOUNTAIN HOA | 96 | 0 |
| CAMELOT HOA | 96 | 0 |
| BUZZ INN | 95 | 0 |
| TALL TIMBERS MOBILE HOME PARK | 90 | 2 |
| MASONIC HOME OF MONTANA | 90 | 0 |
| APPLEGATE VILLAGE | 85 | 0 |
| ELK CREEK COLONY | 84 | 12 |
| SOUTH FORESTVALE HOA | 82 | 1 |
| MITCHELL COURT APARTMENTS | 80 | 0 |
| RUGER WATER DISTRICT | 79 | 0 |
| MCDONALD TRAILER CT | 75 | 2 |
| BARNETT WATER USERS SYSTEM | 70 | 0 |
| MILFORD COLONY INC | 67 | 10 |
| BLUE CLOUD SUBDIVISION | 60 | 26 |
| SUNNYBROOK ACRES HOA | 50 | 0 |
| GRAND VALLEY ESTATES SUBDIVISION | 50 | 0 |
| MOONLIGHT ESTATES HOA | 44 | 0 |
| BROADWATER ESTATES HOA | 40 | 5 |
| PHOENIX PARK | 36 | 1 |
| TRAILS END TR PARK HELENA | 35 | 0 |
| BAHNY BRAE SUBDIVISION | 35 | 0 |
| ROSEMARYS ADDITION | 30 | 0 |
TRI Facilities (5)
| # | Facility | Total Releases |
|---|---|---|
| 1 | American Chemet Corp | 110.6K lbs |
| 2 | US Army National Guard Fort Harrison Ranges | 35.6K lbs |
| 3 | Helena Sand & Gravel Inc | 55 lbs |
| 4 | Forterra Concrete Products - Helena | 0 lbs |
| 5 | Boeing Helena Inc | 0 lbs |
Cities in Lewis And Clark (4)
Frequently Asked Questions
What is the environmental risk level in Lewis And Clark, Montana? ▼
Are there Superfund sites in Lewis And Clark? ▼
How many toxic release facilities are in Lewis And Clark? ▼
What is the air quality in Lewis And Clark? ▼
Is the drinking water safe in Lewis And Clark? ▼
What environmental agencies cover Lewis And Clark? ▼
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.