Marathon, WI
A PlainEnviro-computed score from reported facility/violation counts, not an official EPA rating, health forecast, or population-adjusted rate. See methodology. This is a different measure than the EJ Screening score for this county, which ranks it by percentile against every other tracked county rather than against fixed national thresholds.
Environmental data for Marathon in Wisconsin · Population: 138,067
Marathon, WI is tracked across three EPA datasets covering 37 Toxics Release Inventory (TRI) facilities, 17 Safe Drinking Water Act systems, and 0 Superfund National Priorities List sites. Together these generate an environmental burden score of 66/100 (High Risk), calibrated against national distributions for facility density, chemical release volume, Superfund concentration, and water-system health violations.
Industrial disclosures inside the county total 22.2M lbs of reported toxic releases under EPCRA Section 313, while 11 water systems carry an active health-based violation in the SDWIS record. EPA Air Quality System monitors logged a median AQI of 37 and a peak AQI of 151 in 2024, with 85% 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 | 311 (85%) | 54 | 0 | 151 |
| 2023 | 168 (78%) | 39 | 8 | 166 |
| 2022 | 197 (96%) | 8 | 0 | 64 |
| 2021 | 191 (96%) | 9 | 0 | 87 |
| 2020 | 193 (97%) | 6 | 0 | 74 |
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 Wisconsin, see the EPA's AirNow.gov.
Water Systems (17)
| System | Population | Violations |
|---|---|---|
| WAUSAU WATERWORKS | 39,994 | 0 |
| WESTON MUNICIPAL UTILITIES | 16,000 | 0 |
| KRONENWETTER WATER & SEWER UTILITY | 6,931 | 1 |
| RIB MOUNTAIN WATER UTILITY | 6,398 | 0 |
| MOSINEE WATERWORKS | 3,406 | 1 |
| ROTHSCHILD WATERWORKS | 3,190 | 1 |
| ABBOTSFORD WATERWORKS | 2,502 | 2 |
| SCHOFIELD WATERWORKS | 2,205 | 1 |
| COLBY WATERWORKS | 1,829 | 0 |
| MARATHON CITY WATERWORKS | 1,695 | 2 |
| STRATFORD WATERWORKS | 1,643 | 1 |
| EDGAR WATERWORKS | 1,491 | 1 |
| MOSINEE EAST SYSTEM | 1,046 | 0 |
| ATHENS WATERWORKS | 1,025 | 1 |
| HATLEY WATERWORKS | 550 | 0 |
| MAINE WATER UTILITY | 271 | 2 |
| DEER TRAIL VILLAGE | 120 | 1 |
TRI Facilities (37)
Cities in Marathon (11)
Frequently Asked Questions
What is the environmental risk level in Marathon, Wisconsin? ▼
Are there Superfund sites in Marathon? ▼
How many toxic release facilities are in Marathon? ▼
What is the air quality in Marathon? ▼
Is the drinking water safe in Marathon? ▼
What environmental agencies cover Marathon? ▼
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.