NPDES permits in Wisconsin
391 permits held by publicly owned wastewater treatment plants · issued by WDNR
Effective
6
Administratively continued
36
Expired
349
Total tracked
391
Wisconsin Department of Natural Resources (WDNR) runs the NPDES program in Wisconsin under delegation from EPA Region 5, issuing and enforcing the discharge permits listed here. Klarifi tracks 391 permits held by publicly owned treatment plants in the state, with status, expiry, design flow and three-year compliance for each. Agency website →
An NPDES permit runs for five years. To keep discharging, a plant must apply for renewal at least 180 days before the expiry date, and the renewed permit usually arrives with tighter effluent limits, new monitoring requirements or a compliance schedule. That is why the year a permit expires is the year a plant starts budgeting for upgrades: nutrient removal, disinfection, capacity or controls.
Permit renewals by year
Largest permit holders in Wisconsin
| Facility | City | Avg flow (MGD) | Design (MGD) | NPDES permit | Status | Expires | Violations (3y) |
|---|---|---|---|---|---|---|---|
| Milwaukee Metro Sew Dist Combi | Milwaukee | 95.1 | 123 | WI0036820 | Expired | Mar 2024 | 392 |
| Racine Wastewater Treatment Facility | Racine | 14.44 | 30 | WI0025194 | Expired | Sep 2019 | 6 |
| Kenosha Water Utility Wastewater Treatment Plant | Kenosha | — | 28 | WI0028703 | Expired | Dec 2023 | 2 |
| Green Bay Metropolitan Sewerage District | Green Bay | 27.53 | — | WIL065251 | Effective | Dec 2030 | 7 |
| La Crosse City | La Crosse | 10.29 | 20 | WI0029581 | Administratively continued | Dec 2020 | 0 |
| Oshkosh Wastewater Treatment F | Oshkosh | 8.49 | 20 | WI0025038 | Expired | Dec 2023 | 34 |
| Sheboygan Wastewater Treatment Plant | Sheboygan | — | 18.39 | WI0025411 | Expired | Mar 2026 | 1 |
| Neenah-Menasha Sewerage Commission WWTF | Menasha | — | 18 | WI0026085 | Expired | Jun 2022 | 231 |
| Janesville Wastewater Utility | Janesville | 9.98 | 17.18 | WI0030350 | Expired | Jun 2025 | 0 |
| Eau Claire Wastewater Treatment Facility | Eau Claire | — | 16.26 | WI0023850 | Expired | Mar 2023 | 3 |
| Waukesha Waste Water Treatment Plant | Waukesha | 3.15 | 16 | WI0029971 | Administratively continued | Jun 2018 | 3 |
| Manitowoc WWTP | Manitowoc | — | 15.5 | WI0024601 | Expired | Mar 2023 | 36 |
| Fond Du Lac Water Pollution Co | Fond Du Lac | — | 11.5 | WI0023990 | Expired | Mar 2023 | 0 |
| Fox River Water Pollution Control Center | Brookfield | 8.95 | 10 | WI0023469 | Expired | Dec 2023 | 10 |
| Beloit Wastewater Treatment Facility | Beloit | 3.79 | 9.5 | WI0023370 | Expired | Sep 2025 | 37 |
| Appleton City WWTF | Appleton | 9.25 | — | WI0023221 | Expired | Mar 2022 | 7 |
| Wausau Cty Wastewater Treatment Plt | Wausau | 4.39 | 9.2 | WI0025739 | Expired | Dec 2023 | 0 |
| West Bend City | West Bend | — | 9 | WI0025763 | Expired | Jun 2021 | 0 |
| South Milwaukee Wastewater Tre | South Milwaukee | 2.18 | 6 | WI0028819 | Expired | Dec 2020 | 1 |
| Chippewa Falls WWTP | Chippewa Falls | 1.81 | 5.61 | WI0023604 | Expired | Sep 2025 | 11 |
| Heart Of The Valley Metro Sewage District | Kaukauna | 2.21 | 5.5 | WI0031232 | Expired | Dec 2023 | 1 |
| Watertown Wastewater Treatment | Watertown | 2.81 | 5.2 | WI0028541 | Expired | Sep 2025 | 0 |
| City Of Superior Wastewater Div. Of Public Works | Superior | — | 5 | WI0025593 | Expired | Mar 2024 | 8 |
| Rib Mountain Sewage Dist | Wausau | 2.94 | 4.94 | WI0035581 | Expired | Dec 2023 | 3 |
| Peshtigo City WWTF | Peshtigo | — | 4.65 | WI0030651 | Expired | Jun 2022 | 8 |
NPDES permits in Wisconsin: questions
Sources and methodology
Flow, permit and violation figures come from the EPA's ICIS-NPDES discharge monitoring records. Population served comes from the Clean Watersheds Needs Survey 2022. Treatment structures are identified by Klarifi's review of aerial imagery, and capital improvement projects are extracted from published municipal budget documents. Violations are counted over the last three years of monitoring reports.
Data refreshed September 11, 2026.