The 50 largest wastewater treatment plants in Minnesota
Ranked by average flow · 317 MGD combined · 92% of the state's reported flow
Met Council Metropolitan WWTP in Saint Paul is the largest publicly owned wastewater treatment plant in Minnesota by reported average flow, treating about 164.27 million gallons per day. The 50 plants below treat 317 MGD between them, 92% of the flow reported by all 470 plants in the state, and serve about 3,531,036 people. Every plant links to its profile with permit and compliance data. Treatment technology is shown with a free Klarifi account.
| # | Facility | City | Avg flow (MGD) | Population | NPDES permit | Expires | Violations (3y) |
|---|---|---|---|---|---|---|---|
| 1 | Met Council Metropolitan WWTP | Saint Paul | 164.27 | 2,033,541 | MNL029815 | Dec 2030 | 0 |
| 2 | Blue Lake Wastewater Treatment Plant | Shakopee | 25.9 | 339,518 | MN0029882 | Sep 2029 | 0 |
| 3 | Seneca Wastewater Treatment Plant | Eagan | 20.44 | 324,967 | MN0030007 | Nov 2028 | 6 |
| 4 | Met Council - Empire WWTP | Farmington | 11.65 | 92,175 | MNL045845 | Dec 2030 | 0 |
| 5 | Rochester Water Reclamation Plant | Rochester | 11.39 | 121,395 | MN0024619 | Mar 2027 | 1 |
| 6 | Saint Cloud WWTP | St. Cloud | 9.41 | 19,351 | MNL040878 | Dec 2030 | 0 |
| 7 | Thief River Falls WWTP | Thief River Falls | 6.93 | 8,749 | MN0021431 | Aug 2026 | 29 |
| 8 | Met Council - Eagles Point WWTP | Cottage Grove | 5.99 | 121,176 | MN0029904 | Oct 2023 | 0 |
| 9 | Grand Rapids WWTP | Grand Rapids | 5.92 | 14,815 | MN0022080 | Jan 2025 | 7 |
| 10 | Moorhead Wastewater Treatment Facility | Moorhead | 3.8 | 49,049 | MN0049069 | Jun 2026 | 0 |
| 11 | Owatonna WWTP | Owatonna | 3.32 | 26,420 | MN0051284 | May 2026 | 10 |
| 12 | Alexandria Lake Area Sanitary District | Alexandria | 2.75 | 28,749 | MN0040738 | Jul 2030 | 0 |
| 13 | Met Council - St Croix Valley WWTP | Oak Park Heights | 2.44 | 24,908 | MN0029998 | May 2027 | 0 |
| 14 | Whitewater River Regional WWTP | Saint Charles | 2.35 | 6,629 | MN0046868 | Oct 2027 | 13 |
| 15 | Mahnomen WWTP | Mahnomen | 2.32 | 1,428 | MN0024066 | Sep 2029 | 71 |
| 16 | Marshall WWTP | Marshall | 2.15 | 13,628 | MN0022179 | Feb 2029 | 16 |
| 17 | Litchfield WWTP | Litchfield | 1.94 | 6,624 | MN0023973 | Dec 2030 | 22 |
| 18 | Northfield WWTP | Northfield | 1.86 | 23,826 | MN0024368 | Sep 2031 | 0 |
| 19 | Red Wing WWTP | Red Wing | 1.65 | 16,547 | MNL024571 | Dec 2030 | 0 |
| 20 | Saint Peter WWTP | Saint Peter | 1.46 | 12,780 | MN0022535 | Mar 2027 | 8 |
| 21 | Met Council Hastings WWTP | Hastings | 1.42 | 22,154 | MN0029955 | Mar 2030 | 0 |
| 22 | Fergus Falls WWTP | Fergus Falls | 1.39 | 14,119 | MN0050628 | Aug 2028 | 2 |
| 23 | Elk River WWTP | Elk River | 1.31 | 26,090 | MNL020788 | Dec 2030 | 1 |
| 24 | Barnesville WWTP | Barnesville | 1.26 | 2,464 | MN0022501 | Apr 2026 | 98 |
| 25 | Rogers WWTP | Rogers | 1.16 | 13,295 | MN0029629 | Mar 2026 | 5 |
| 26 | Cold Spring WWTP | Cold Spring | 1.11 | 2,382 | MNL023094 | Dec 2030 | 0 |
| 27 | Long Prairie WWTP | Long Prairie | 1.1 | — | MN0066079 | Apr 2023 | 2 |
| 28 | Buffalo WWTP | Buffalo | 1.08 | 16,210 | MNL040649 | Dec 2030 | 1 |
| 29 | Monticello WWTP | Monticello | 1.04 | 14,455 | MN0020567 | Jul 2031 | 106 |
| 30 | Detroit Lakes WWTP | Detroit Lakes | 1.04 | 9,869 | MN0020192 | Apr 2026 | 3 |
| 31 | Virginia WWTP | Virginia | 1.03 | 10,244 | MN0030163 | Mar 2026 | 1 |
| 32 | Saint Michael WWTP | Saint Michael | 1.03 | 21,733 | MN0020222 | Nov 2030 | 24 |
| 33 | Bemidji WWTP | Bemidji | 1.02 | 14,759 | MN0022462 | Mar 2026 | 0 |
| 34 | Chisago Lakes Joint Stc | Chisago City | 1.02 | 9,426 | MN0055808 | Mar 2030 | 3 |
| 35 | Grove City WWTP | Grove City | 0.98 | 624 | MN0023574 | Mar 2022 | 1 |
| 36 | Redwood Falls WWTP | Redwood Falls | 0.91 | 5,838 | MN0020401 | Dec 2027 | 26 |
| 37 | Clarkfield WWTP | Clarkfield | 0.91 | 1,044 | MNG585093 | Nov 2028 | 33 |
| 38 | Becker WWTP | Becker | 0.9 | 5,277 | MN0025666 | Sep 2029 | 10 |
| 39 | Montevideo WWTP | Montevideo | 0.88 | 5,863 | MN0020133 | Apr 2019 | 27 |
| 40 | Luverne WWTP | Luverne | 0.83 | 4,938 | MN0020141 | Apr 2030 | 2 |
| 41 | Smsc Water Reclamation Facili | Prior Lake | 0.82 | — | MN0067938 | Apr 2023 | 7 |
| 42 | Fortune Bay Resort & Casino | Tower | 0.78 | — | MN0061310 | Jan 2030 | 25 |
| 43 | Two Harbors WWTP | Two Harbors | 0.76 | 3,941 | MN0022250 | Oct 2030 | 0 |
| 44 | Nkasd WWTP | International Falls | 0.75 | 6,996 | MN0020257 | Feb 2026 | 5 |
| 45 | Big Lake WWTP | Big Lake | 0.73 | 11,686 | MN0041076 | Mar 2023 | 0 |
| 46 | New Prague WWTP | New Prague | 0.68 | 8,162 | MNL020150 | Dec 2030 | 11 |
| 47 | Cambridge WWTP | Cambridge | 0.68 | 9,273 | MN0020362 | Mar 2031 | 2 |
| 48 | Annandale/maple Lake WWTF | Maple Lake | 0.67 | 2,177 | MN0066966 | May 2031 | 6 |
| 49 | Winnebago WWTP | Winnebago | 0.66 | 1,742 | MNL025267 | Dec 2030 | 12 |
| 50 | Crystal Lake Flocculation Treatment Facility | Robbinsdale | 0.66 | — | MN0069957 | Mar 2031 | 52 |
Treatment technology for each plant is shown with a free Klarifi account. Create one →
Largest plants in Minnesota: 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 October 26, 2026.
Wastewater terms: WWTP · POTW · MGD · NPDES permit · Anaerobic digester · Lift station · all terms
Cite this page
Journalists, researchers and educators are welcome to quote these figures. Please credit Klarifi as the source and link to this page.
Klarifi. “Largest wastewater treatment plants in Minnesota (2026).” Updated October 26, 2026. https://klarifi.io/facilities/minnesota/largestNeed a custom cut of the data for a state, a county or a list of plants? Email info@klarifi.io.