The 50 largest wastewater treatment plants in Minnesota
Ranked by average flow · 318 MGD combined · 93% 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 180 million gallons per day. The 50 plants below treat 318 MGD between them, 93% of the flow reported by all 460 plants in the state, and serve about 3,534,050 people. Every plant links to its profile with permit, technology and compliance data.
| # | Facility | City | Avg flow (MGD) | Population | NPDES permit | Expires | Technology | Violations (3y) |
|---|---|---|---|---|---|---|---|---|
| 1 | Met Council Metropolitan WWTP | Saint Paul | 180 | 2,033,541 | MNL029815 | Dec 2030 | Biogas silos | 0 |
| 2 | Blue Lake Wastewater Treatment Plant | Shakopee | 26.54 | 339,518 | MN0029882 | Sep 2029 | Biogas silos, Biogas balloons | 0 |
| 3 | Seneca Wastewater Treatment Plant | Eagan | 20.92 | 324,967 | MN0030007 | Nov 2028 | Clarifiers | 6 |
| 4 | Met Council - Empire WWTP | Farmington | 12.05 | 92,175 | MNL045845 | Dec 2030 | Clarifiers, Uncovered lagoons, Biogas silos, Biogas balloons | 0 |
| 5 | Rochester Water Reclamation Plant | Rochester | 11.33 | 121,395 | MN0024619 | Mar 2027 | Clarifiers, Biogas silos, Biogas balloons | 1 |
| 6 | Met Council - Eagles Point WWTP | Cottage Grove | 6 | 121,176 | MN0029904 | Oct 2023 | Clarifiers | 1 |
| 7 | Grand Rapids WWTP | Grand Rapids | 5.8 | 14,815 | MN0022080 | Jan 2025 | Clarifiers, Uncovered lagoons | 6 |
| 8 | Moorhead Wastewater Treatment Facility | Moorhead | 3.82 | 49,049 | MN0049069 | Jun 2026 | Uncovered lagoons, Biogas silos, Biogas balloons | 0 |
| 9 | Owatonna WWTP | Owatonna | 3.16 | 26,420 | MN0051284 | May 2026 | Clarifiers, Biogas silos, Biogas balloons | 9 |
| 10 | Albert Lea Wastewater Treatment Facility | Albert Lea | 3.06 | 19,344 | MN0041092 | Jan 2027 | Clarifiers, Biogas silos, Biogas balloons | 1 |
| 11 | Alexandria Lake Area Sanitary District | Alexandria | 2.95 | 28,749 | MN0040738 | Jul 2030 | Clarifiers, Biogas balloons | 0 |
| 12 | Met Council - St Croix Valley WWTP | Oak Park Heights | 2.54 | 24,908 | MN0029998 | May 2027 | Clarifiers, Biogas silos | 0 |
| 13 | Marshall WWTP | Marshall | 2.51 | 13,628 | MN0022179 | Feb 2029 | Clarifiers, Uncovered lagoons, Biogas silos, Biogas balloons | 16 |
| 14 | Northfield WWTP | Northfield | 2.15 | 23,826 | MN0024368 | May 2025 | Clarifiers | 0 |
| 15 | Litchfield WWTP | Litchfield | 2 | 6,624 | MN0023973 | Dec 2030 | Clarifiers, Biogas silos, Biogas balloons | 22 |
| 16 | Saint Peter WWTP | Saint Peter | 1.9 | 12,780 | MN0022535 | Mar 2027 | Uncovered lagoons | 15 |
| 17 | Red Wing WWTP | Red Wing | 1.66 | 16,547 | MNL024571 | Dec 2030 | Clarifiers, Biogas silos, Biogas balloons | 0 |
| 18 | Elk River WWTP | Elk River | 1.6 | 26,090 | MNL020788 | Dec 2030 | Biogas silos, Biogas balloons | 1 |
| 19 | Met Council Hastings WWTP | Hastings | 1.53 | 22,154 | MN0029955 | Mar 2030 | Clarifiers | 0 |
| 20 | Long Prairie WWTP | Long Prairie | 1.51 | — | MN0066079 | Apr 2023 | Aerated lagoons, Covered lagoons, Uncovered lagoons, Biogas balloons | 2 |
| 21 | Fergus Falls WWTP | Fergus Falls | 1.44 | 14,119 | MN0050628 | Aug 2028 | Clarifiers, Biogas silos | 2 |
| 22 | Montevideo WWTP | Montevideo | 1.35 | 5,863 | MN0020133 | Apr 2019 | Biogas silos, Biogas balloons | 27 |
| 23 | Buffalo WWTP | Buffalo | 1.23 | 16,210 | MNL040649 | Dec 2030 | Uncovered lagoons, Carrousels / oxidation ditches, Biogas balloons | 1 |
| 24 | Cold Spring WWTP | Cold Spring | 1.16 | 2,382 | MNL023094 | Dec 2030 | Uncovered lagoons, Biogas silos, Biogas balloons | 0 |
| 25 | Rogers WWTP | Rogers | 1.09 | 13,295 | MN0029629 | Mar 2026 | Aerated lagoons, Uncovered lagoons, Carrousels / oxidation ditches, Biogas balloons | 5 |
| 26 | Bemidji WWTP | Bemidji | 1.09 | 14,759 | MN0022462 | Mar 2026 | Biogas silos, Biogas balloons | 0 |
| 27 | Monticello WWTP | Monticello | 1.05 | 14,455 | MN0020567 | Jul 2031 | Biogas silos, Biogas balloons | 106 |
| 28 | Chisago Lakes Joint Stc | Chisago City | 1.03 | 9,426 | MN0055808 | Mar 2030 | Uncovered lagoons | 3 |
| 29 | Saint Michael WWTP | Saint Michael | 0.96 | 21,733 | MN0020222 | Nov 2030 | Biogas balloons | 24 |
| 30 | Virginia WWTP | Virginia | 0.94 | 10,244 | MN0030163 | Mar 2026 | Biogas balloons | 1 |
| 31 | Becker WWTP | Becker | 0.91 | 5,277 | MN0025666 | Sep 2029 | Clarifiers, Carrousels / oxidation ditches, Biogas balloons | 10 |
| 32 | Redwood Falls WWTP | Redwood Falls | 0.89 | 5,838 | MN0020401 | Dec 2027 | Biogas balloons | 26 |
| 33 | Fortune Bay Resort & Casino | Tower | 0.83 | — | MN0061310 | Jan 2030 | — | 25 |
| 34 | Luverne WWTP | Luverne | 0.79 | 4,938 | MN0020141 | Apr 2030 | Clarifiers, Carrousels / oxidation ditches, Biogas silos, Biogas balloons | 3 |
| 35 | Two Harbors WWTP | Two Harbors | 0.77 | 3,941 | MN0022250 | Oct 2030 | — | 4 |
| 36 | Big Lake WWTP | Big Lake | 0.74 | 11,686 | MN0041076 | Mar 2023 | Carrousels / oxidation ditches, Biogas balloons | 0 |
| 37 | Smsc Water Reclamation Facili | Prior Lake | 0.74 | — | MN0067938 | Apr 2023 | Uncovered lagoons | 7 |
| 38 | New Prague WWTP | New Prague | 0.7 | 8,162 | MNL020150 | Dec 2030 | Uncovered lagoons | 9 |
| 39 | Annandale/maple Lake WWTF | Maple Lake | 0.69 | 2,177 | MN0066966 | May 2031 | — | 6 |
| 40 | Crystal Lake Flocculation Treatment Facility | Robbinsdale | 0.68 | — | MN0069957 | Mar 2031 | — | 52 |
| 41 | Cambridge WWTP | Cambridge | 0.65 | 9,273 | MN0020362 | Mar 2031 | Biogas silos, Biogas balloons | 2 |
| 42 | Kasson WWTP | Kasson | 0.64 | 7,944 | MN0050725 | Dec 2028 | Carrousels / oxidation ditches, Biogas silos, Biogas balloons | 0 |
| 43 | Chisholm WWTP | Chisholm | 0.64 | 150 | MN0020117 | Jan 2027 | Uncovered lagoons, Biogas silos, Biogas balloons | 10 |
| 44 | Plainview-Elgin Sanitary District WWTP | Plainview | 0.62 | 4,598 | MN0055361 | Nov 2027 | Biogas silos | 2 |
| 45 | Green Lake Sswd | Spicer | 0.6 | 3,001 | MN0052752 | Dec 2026 | Biogas balloons | 0 |
| 46 | Stewartville WWTP | Stewartville | 0.6 | 6,466 | MN0020681 | Nov 2029 | Clarifiers, Uncovered lagoons, Carrousels / oxidation ditches, Biogas balloons | 4 |
| 47 | Madelia WWTP | Madelia | 0.59 | 2,396 | MN0024040 | Apr 2029 | — | 9 |
| 48 | Granite Falls WWTP | Granite Falls | 0.59 | 3,076 | MN0021211 | Dec 2027 | — | 9 |
| 49 | Whitewater River Regional WWTP | Saint Charles | 0.58 | 6,629 | MN0046868 | Oct 2027 | Uncovered lagoons, Carrousels / oxidation ditches, Biogas balloons | 13 |
| 50 | Albertville WWTP | Albertville | 0.58 | 8,306 | MN0050954 | May 2024 | Uncovered lagoons, Carrousels / oxidation ditches, Biogas balloons | 0 |
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 September 11, 2026.