The 50 largest wastewater treatment plants in Missouri
Ranked by average flow · 403 MGD combined · 83% of the state's reported flow
Metropolitan St. Louis Sewer District Bissell Point WWTP in St. Louis is the largest publicly owned wastewater treatment plant in Missouri by reported average flow, treating about 90.1 million gallons per day. The 50 plants below treat 403 MGD between them, 83% of the flow reported by all 593 plants in the state, and serve about 2,871,361 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 | Metropolitan St. Louis Sewer District Bissell Point WWTP | St. Louis | 90.1 | 304,678 | MO0025178 | Aug 2031 | Clarifiers, Biogas balloons | 14 |
| 2 | Metropolitan St. Louis Sewer District Lemay WWTP | St. Louis | 79.3 | 453,428 | MO0025151 | Aug 2031 | Clarifiers, Biogas silos | 0 |
| 3 | Little Blue Valley Sewer District | Independence | 29.2 | 39,046 | MOL101087 | Dec 2030 | Clarifiers, Aerated lagoons, Covered lagoons, Carrousels / oxidation ditches, Biogas silos, Biogas balloons | 14 |
| 4 | Southwest WWTP | Springfield | 25.32 | 206,375 | MO0049522 | Jul 2025 | Clarifiers, Aerated lagoons, Uncovered lagoons, Carrousels / oxidation ditches, Biogas silos, Biogas balloons | 0 |
| 5 | St. Joseph Water Protection Facility | Saint Joseph | 18.27 | 77,300 | MO0023043 | Nov 2025 | Clarifiers, Biogas silos | 4 |
| 6 | MSD Coldwater WWTP | Florissant | 14.3 | 160,833 | MO0025160 | Aug 2031 | Clarifiers, Biogas silos | 1 |
| 7 | Kc, Westside WWTP | Kansas City | 12.54 | 227,510 | MO0024929 | Jun 2026 | Clarifiers, Biogas silos, Biogas balloons | 2 |
| 8 | Metropolitan St Louis Sewer District-Grand Glaize Wastewater Treatment Plant | Valley Park | 10.4 | 113,693 | MO0101362 | Aug 2031 | Clarifiers, Carrousels / oxidation ditches, Biogas silos | 0 |
| 9 | MSD Lower Meramec WWTP | St. Louis | 7.6 | 68,482 | MO0127949 | Aug 2031 | Clarifiers, Aerated lagoons, Uncovered lagoons, Biogas silos, Biogas balloons | 0 |
| 10 | O' Fallon Wastewater Treatment Plant | O'Fallon | 6.7 | 88,132 | MO0028720 | Mar 2025 | Clarifiers, Uncovered lagoons, Biogas balloons | 0 |
| 11 | Joplin Turkey Creek WWTP | Joplin | 5.7 | 53,845 | MO0103349 | Sep 2022 | Clarifiers, Uncovered lagoons, Carrousels / oxidation ditches, Biogas silos | 64 |
| 12 | Shoal Creek Wastewater Treatment Facility | Joplin | 5.6 | 34,800 | MO0023256 | Mar 2023 | Clarifiers, Uncovered lagoons, Carrousels / oxidation ditches, Biogas silos | 9 |
| 13 | Jefferson City Rwrf | Jefferson City | 5.36 | 43,841 | MO0094846 | Mar 2025 | Clarifiers | 0 |
| 14 | Rock Creek Waste Treatment | Independence | 5.07 | 113,681 | MO0089681 | Mar 2024 | Clarifiers | 12 |
| 15 | St Peters Pws | Saint Peters | 4.83 | 57,536 | MO0030970 | Dec 2024 | Clarifiers, Carrousels / oxidation ditches, Biogas silos | 0 |
| 16 | Cape Girardeau WWTP | Cape Girardeau | 4.36 | 40,100 | MO0136328 | Jun 2024 | — | 0 |
| 17 | Wentzville Pws | Wentzville | 4.34 | 41,342 | MO0093599 | Mar 2024 | Clarifiers | 4 |
| 18 | Dcsd Wastewater Treatment Plant 2 | Weldon Spring | 4.28 | 5,536 | MO0116572 | Dec 2025 | Clarifiers, Uncovered lagoons, Carrousels / oxidation ditches | 0 |
| 19 | Springfield NW WWTP | Springfield | 4.06 | 6,344 | MO0103039 | Jul 2025 | Clarifiers, Uncovered lagoons, Carrousels / oxidation ditches, Biogas balloons | 0 |
| 20 | Duckett Creek Sanitation District Treatment Plant #1 | Saint Charles | 4.04 | 5,439 | MO0085472 | Jun 2021 | Clarifiers, Carrousels / oxidation ditches | 0 |
| 21 | St Charles Missouri River WWTP | St. Charles | 3.73 | 70,650 | MO0058351 | Sep 2025 | Clarifiers, Aerated lagoons, Uncovered lagoons, Carrousels / oxidation ditches | 0 |
| 22 | MSD Fenton Waste Water Treatment Plant | Fenton | 3.6 | 21,144 | MO0086126 | Dec 2022 | Clarifiers, Carrousels / oxidation ditches | 0 |
| 23 | Blue Springs, Sni A Bar WWTF | Grain Valley | 3.5 | 42,549 | MO0028886 | Nov 2028 | Clarifiers, Aerated lagoons, Uncovered lagoons | 16 |
| 24 | Poplar Bluff Municipal WWTP | Poplar Bluff | 3.18 | 16,979 | MO0043648 | Sep 2024 | Covered lagoons, Uncovered lagoons | 4 |
| 25 | Carthage WWTP | Carthage | 2.92 | 74,700 | MO0039136 | Mar 2023 | Clarifiers, Uncovered lagoons | 4 |
| 26 | Hannibal Pws | Hannibal | 2.69 | 17,312 | MO0093513 | Apr 2023 | Clarifiers, Biogas balloons | 0 |
| 27 | Monett Wastewater Treatment Plant | Monett | 2.5 | 75,312 | MO0021440 | Jun 2029 | Clarifiers, Carrousels / oxidation ditches | 17 |
| 28 | Branson Compton Drive WWTP | Branson | 2.26 | 59,086 | MO0025241 | Sep 2024 | Clarifiers, Carrousels / oxidation ditches, Biogas balloons | 1 |
| 29 | Sikeston WWTP | Sikeston | 2.23 | 30,000 | MO0035009 | Sep 2025 | Clarifiers, Carrousels / oxidation ditches, Biogas silos | 0 |
| 30 | Lebanon WWTP | Lebanon | 2.22 | 14,735 | MO0089010 | Dec 2021 | Clarifiers, Aerated lagoons, Carrousels / oxidation ditches | 1 |
| 31 | Marshall SE WWTP | Marshall | 2.22 | 12,920 | MO0032883 | Mar 2022 | Clarifiers, Uncovered lagoons | 0 |
| 32 | Rolla Pws-Well 4 - E 10th St | Rolla | 2.17 | 47,650 | MO0050652 | Jun 2023 | Clarifiers, Uncovered lagoons, Carrousels / oxidation ditches | 0 |
| 33 | Kirksville WWTP | Kirksville | 2.02 | 17,645 | MO0049506 | Dec 2027 | Clarifiers, Aerated lagoons, Uncovered lagoons | 0 |
| 34 | Hollister WWTF | Hollister | 2 | 3,000 | MO0116041 | Dec 2024 | Clarifiers, Aerated lagoons, Uncovered lagoons, Carrousels / oxidation ditches | 2 |
| 35 | Neosho WWTP | Neosho | 2 | 29,000 | MO0104906 | Apr 2022 | Clarifiers, Aerated lagoons, Uncovered lagoons, Carrousels / oxidation ditches | 27 |
| 36 | Festus-Crystal City WWTP | Crystal City | 1.81 | 7,500 | MO0080632 | Sep 2021 | — | 14 |
| 37 | Branson Cooper Creek WWTP | Branson | 1.73 | 34,000 | MO0116599 | Sep 2024 | Uncovered lagoons | 2 |
| 38 | Npsd Interim Saline Creek Regional WWTP | Fenton | 1.71 | 888 | MO0128490 | Jun 2023 | Clarifiers, Uncovered lagoons, Carrousels / oxidation ditches | 0 |
| 39 | Washington WWTP | Washington | 1.65 | 4,684 | MO0025810 | Mar 2026 | Clarifiers | 2 |
| 40 | Center Creek WWTP | Webb City | 1.57 | 11,884 | MO0040185 | Apr 2030 | Clarifiers, Uncovered lagoons, Carrousels / oxidation ditches | 151 |
| 41 | Camelot Estates WWTP | Camdenton | 1.55 | — | MO0133817 | Mar 2030 | Clarifiers, Aerated lagoons, Uncovered lagoons | 0 |
| 42 | Pleasant Hill Pws | Pleasant Hill | 1.53 | 21,568 | MO0058629 | Mar 2026 | Clarifiers, Aerated lagoons, Uncovered lagoons | 0 |
| 43 | Nixa WWTF | Nixa | 1.52 | 22,086 | MO0028037 | Jun 2028 | Clarifiers, Uncovered lagoons, Carrousels / oxidation ditches | 16 |
| 44 | West Plains Pws-West Plains Treatment Plt | West Plains | 1.46 | 12,290 | MO0096610 | Mar 2023 | Clarifiers, Carrousels / oxidation ditches | 18 |
| 45 | Kimmswick WWTP | Imperial | 1.42 | 16,000 | MO0106461 | Aug 2028 | Uncovered lagoons | 2 |
| 46 | Republic WWTP | Republic | 1.38 | 16,571 | MO0022098 | Jul 2029 | Clarifiers, Aerated lagoons, Uncovered lagoons, Carrousels / oxidation ditches | 5 |
| 47 | Fulton WWTP | Fulton | 1.37 | 12,696 | MO0103331 | Nov 2028 | Clarifiers, Uncovered lagoons, Carrousels / oxidation ditches | 17 |
| 48 | Lake Of The Ozarks Regional WWTP 1 | Lake Ozark | 1.36 | 4,923 | MO0103241 | Dec 2025 | Clarifiers, Carrousels / oxidation ditches | 12 |
| 49 | Sunny Slope Country Club Drive WWTP | Camdenton | 1.35 | 1,348 | MO0130591 | Jun 2024 | Clarifiers, Carrousels / oxidation ditches | 0 |
| 50 | Sedalia Central WWTP | Sedalia | 1.28 | 30,300 | MO0023019 | Oct 2028 | Clarifiers, Aerated lagoons, Uncovered lagoons | 57 |
Largest plants in Missouri: 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.