MPDES Individual Permits
Major MPDES Permits
Major municipal dischargers include all facilities with design flows of greater than one million gallons per day and facilities with EPA/State approved industrial pretreatment programs. Major industrial facilities are determined based on specific ratings criteria developed by EPA/State. Below is a listing of all active permits in Montana, issued by the department, that are classified as major dischargers.
| Permit Number | Facility Name | Permittee Name | Location |
| MT0000035 | Frenchtown Mill Site | M2Green Redevelopment, LLC | Missoula, MT |
| MT0000191 | Montana Resources | Montana Resources | Butte, MT |
| MT0000205 | Stimson Lumber Company | Stimson Lumber Company | Bonner, MT |
| MT0000248 | Sugar Beet Processing Facility | Sidney Sugars, Inc | Richland County, MT |
| MT0000256 | ConocoPhillips Billings Refinery | ConocoPhillips Company | Billings, MT |
| MT0000264 | Cenex Harvest States Cooperatives | Cenex Harvest States Cooperatives | Laurel, MT |
| MT0000281 | Sugar Beet Processing Facility | Western Sugar Cooperative | Yellowstone County, MT |
| MT0000302 | Lewis & Clark Station Steam Electric Power Plant | Montana-Dakota Utilities Co. | Sidney, MT |
| MT0000396 | Corette Steam Electric Power Plant | PPL Montana, LLC | Billings, MT |
| MT0000477 | ExxonMobil Billings Refinery | ExxonMobil Corporation | Billings, MT |
| MT0000892 | Decker West Mine | Decker Coal Company | Bighorn County, MT |
| MT0020001 | City of Miles City Domestic Wastewater Treatment Plant | City of Miles City | Miles City, MT |
| MT0020028 | City of Hamilton Domestic Wastewater Treatment Plant | City of Hamilton | Hamilton, MT |
| MT0020044 | City of Lewistown Domestic Wastewater Treatment Facilities | City of Lewistown | Lewistown, MT |
| MT0020184 | City of Whitefish Domestic Wastewater Treatment Plant | City of Whitefish | Whitefish, MT |
| MT0020311 | City of Laurel Wastewater Plant | City of Laurel | Laurel, MT |
| MT0020397 | Bigfork County Water and Sewer District Domestic Wastewater Treatment Plant | Bigfork County Water and Sewer District | Bigfork, Flathead Counties, MT |
| MT0020435 | City of Livingston Domestic Wastewater Treatment Plant | City of Livingston | Livingston, MT |
| MT0020478 | City of Red Lodge Domestic Wastewater Plant | City of Red Lodge | Red Lodge, MT |
| MT0020494 | City of Libby Domestic Wastewater Treatment Plant | City of Libby | Libby, MT |
| MT0021628 | City of Glendive Domestic Wastewater Treatment Lagoon | City of Glendive | Glendive, MT |
| MT0021920 | City of Great Falls Domestic Wastewater Treatment Plant | City of Great Falls | Great Falls, MT |
| MT0021938 | City of Kalispell Domestic Wastewater Treatment Plant | City of Kalispell | Kalispell, MT |
| MT0022012 | City and County of Butte-Silver Bow Domestic Wastewater Treatment Facilities | City and County of Butte-Silver Bow | Butte, MT |
| MT0022535 | City of Havre Domestic Wastewater Treatment Plant | City of Havre | Havre, MT |
| MT0022586 | City of Billings Sewage Treatment Plant | City of Billings | Billings, MT |
| MT0022594 | City of Missoula Domestic Wastewater Treatment Facilities | City of Missoula | Missoula, MT |
| MT0022608 | City of Bozeman Domestic Wastewater Treatment Facilities | City of Bozeman | Bozeman, MT |
| MT0022616 | City of Deer Lodge Domestic Wastewater Treatment Facility | City of Deer Lodge | Deer Lodge, MT |
| MT0022641 | City of Helena Domestic Wastewater Treatment Plant | City of Helena | Helena, MT |
| MT0023965 | Rosebud Mine | Western Energy Company | Colstrip, MT |
| MT0024210 | Decker East Mine | Decker Coal Company | Blaine County, MT |
| MT0025020 | Montana Gold and Sapphires Suction Dredge Project | Montana Gold and Sapphires, Inc | Lewis and Clark County, MT |
Minor MPDES Permits
Minor municipal dischargers include all facilities that do not meet the classification criteria of a Major discharger. Below is a listing of all active permits in Montana, issued by the department, that are classified as minor dischargers.
| Permit Number | Facility Name | Permittee Name | Location |
Ground Water MGWPCS Permits
MGWPCS Permits are for facilities that discharge to state ground waters. Below is a listing of all active permits in Montana, issued by the department, that discharge to state ground waters.
| Permit Number | Facility Name | Permittee Name | Location |
