Lagoon systems: wastewater treatment plants in Missouri
290 plants · 49% of the state · 176 MGD reported by 247 plants
Klarifi identifies 290 publicly owned wastewater treatment plants with lagoon systems in Missouri, 49% of the 593 plants in the state (176 MGD reported by 247 plants). The largest is Little Blue Valley Sewer District in Independence at 29.2 MGD.
Lagoon systems treat wastewater in large earthen ponds over weeks of retention time, with or without mechanical aeration. They serve thousands of small towns because they are cheap to run, but they struggle with ammonia and nutrient limits, fill with sludge over decades and are the plants most often converted or upgraded when a permit is renewed.
The largest lagoons in Missouri
| # | Facility | City | Avg flow (MGD) | NPDES permit | Expires | Violations (3y) |
|---|---|---|---|---|---|---|
| 1 | Little Blue Valley Sewer District | Independence | 29.2 | MOL101087 | Dec 2030 | 14 |
| 2 | Southwest WWTP | Springfield | 25.32 | MO0049522 | Jul 2025 | 0 |
| 3 | MSD Lower Meramec WWTP | St. Louis | 7.6 | MO0127949 | Aug 2031 | 0 |
| 4 | O' Fallon Wastewater Treatment Plant | O'Fallon | 6.7 | MO0028720 | Mar 2025 | 0 |
| 5 | Joplin Turkey Creek WWTP | Joplin | 5.7 | MO0103349 | Sep 2022 | 64 |
| 6 | Shoal Creek Wastewater Treatment Facility | Joplin | 5.6 | MO0023256 | Mar 2023 | 9 |
| 7 | Dcsd Wastewater Treatment Plant 2 | Weldon Spring | 4.28 | MO0116572 | Dec 2025 | 0 |
| 8 | Springfield NW WWTP | Springfield | 4.06 | MO0103039 | Jul 2025 | 0 |
| 9 | St Charles Missouri River WWTP | St. Charles | 3.73 | MO0058351 | Sep 2025 | 0 |
| 10 | Blue Springs, Sni A Bar WWTF | Grain Valley | 3.5 | MO0028886 | Nov 2028 | 16 |
| 11 | Poplar Bluff Municipal WWTP | Poplar Bluff | 3.18 | MO0043648 | Sep 2024 | 4 |
| 12 | Carthage WWTP | Carthage | 2.92 | MO0039136 | Mar 2023 | 4 |
| 13 | Branson Compton Drive WWTP | Branson | 2.26 | MO0025241 | Sep 2024 | 1 |
| 14 | Lebanon WWTP | Lebanon | 2.22 | MO0089010 | Dec 2021 | 1 |
| 15 | Marshall SE WWTP | Marshall | 2.22 | MO0032883 | Mar 2022 | 0 |
| 16 | Rolla Pws-Well 4 - E 10th St | Rolla | 2.17 | MO0050652 | Jun 2023 | 0 |
| 17 | Kirksville WWTP | Kirksville | 2.02 | MO0049506 | Dec 2027 | 0 |
| 18 | Hollister WWTF | Hollister | 2 | MO0116041 | Dec 2024 | 2 |
| 19 | Neosho WWTP | Neosho | 2 | MO0104906 | Apr 2022 | 27 |
| 20 | Branson Cooper Creek WWTP | Branson | 1.73 | MO0116599 | Sep 2024 | 2 |
| 21 | Npsd Interim Saline Creek Regional WWTP | Fenton | 1.71 | MO0128490 | Jun 2023 | 0 |
| 22 | Center Creek WWTP | Webb City | 1.57 | MO0040185 | Apr 2030 | 151 |
| 23 | Camelot Estates WWTP | Camdenton | 1.55 | MO0133817 | Mar 2030 | 0 |
| 24 | Pleasant Hill Pws | Pleasant Hill | 1.53 | MO0058629 | Mar 2026 | 0 |
| 25 | Nixa WWTF | Nixa | 1.52 | MO0028037 | Jun 2028 | 16 |
Plants planning lagoon systems upgrades
These plants report lagoon systems as a planned process in the EPA Clean Watersheds Needs Survey: the earliest public signal of a project.
| Facility | City | Avg flow (MGD) | NPDES permit | Expires |
|---|---|---|---|---|
| Tarkio WWTF | Tarkio | 0.16 | MO0051608 | Apr 2028 |
| Ellington WWTF | Ellington | 0.14 | MO0022896 | Dec 2024 |
| Unionville Pws | Unionville | 0.09 | MO0026646 | Apr 2029 |
| Bland Pws | Bland | 0.08 | MO0055395 | Mar 2025 |
| Brunswick WWTF | Brunswick | 0.04 | MO0032557 | Jun 2028 |
| Labelle WWTF | La Belle | 0.005 | MO0100684 | Nov 2030 |
| Annapolis Pws | Annapolis | — | MO0023621 | Dec 2026 |
| Appleton City WWTF | Appleton City | — | MO0021105 | Jun 2027 |
| Fillmore WWTF | Fillmore | — | MO0117722 | Aug 2030 |
| Pocahontas WWTF | Pocahontas | — | MO0130150 | Sep 2030 |
Contacts and project signals for every plant on this list
Klarifi adds verified decision-maker contacts, permit limits, discharge monitoring data and the capital projects planned in each city, filterable by technology, size and compliance record.
Other technologies in Missouri
Lagoon systems in other states
Lagoon systems 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.