Lagoon systems: wastewater treatment plants in Wyoming
43 plants · 77% of the state · 28 MGD reported by 28 plants
Klarifi identifies 43 publicly owned wastewater treatment plants with lagoon systems in Wyoming, 77% of the 56 plants in the state (28 MGD reported by 28 plants). The largest is Pine Bluffs Wastewater Lagoon in Pine Bluffs at 10 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 Wyoming
| # | Facility | City | Avg flow (MGD) | NPDES permit | Expires | Violations (3y) |
|---|---|---|---|---|---|---|
| 1 | Pine Bluffs Wastewater Lagoon | Pine Bluffs | 10 | WY0032212 | Apr 2029 | 273 |
| 2 | Sam H. Hobbs Regional WW Facility (prev. Casper Wwtf) | Casper | 6.67 | WY0021920 | Oct 2030 | 13 |
| 3 | Gillette WWTF | Gillette | 2.92 | WY0020125 | Jul 2027 | 7 |
| 4 | Jackson Wastewater Lagoon | Jackson | 1.94 | WY0021458 | Oct 2029 | 3 |
| 5 | Lander Wastewater Lagoon | Lander | 1.24 | WY0020389 | Apr 2026 | 43 |
| 6 | Buffalo WWTP | Buffalo | 0.79 | WY0021024 | Oct 2026 | 0 |
| 7 | Cody Wastewater Lagoon | Cody | 0.6 | WY0020451 | Jan 2030 | 1 |
| 8 | Basin Wastewater Lagoon | Basin | 0.55 | WY0020028 | Dec 2026 | 38 |
| 9 | Douglas Wastewater Lagoon | Douglas | 0.49 | WY0020109 | Oct 2030 | 4 |
| 10 | Torrington Wastewater Lagoons | Torrington | 0.46 | WY0020231 | Jul 2029 | 18 |
| 11 | Lyman Wastewater Lagoon | Lyman | 0.4 | WY0020117 | Sep 2027 | 47 |
| 12 | Green River Wastewater Treatment Plant | Green River | 0.37 | WY0020443 | Jun 2031 | 13 |
| 13 | Marbleton Wastewater Lagoon | Marbleton | 0.31 | WY0021997 | Mar 2024 | 158 |
| 14 | Moorcroft Wastewater Lagoon | Moorcroft | 0.21 | WY0021741 | Jan 2031 | 28 |
| 15 | Mountain View Wastewater Lagoon | Mountain View | 0.2 | WY0022896 | Apr 2030 | 48 |
| 16 | Big Piney Wastewater Lagoon | Big Piney | 0.14 | WY0020133 | Mar 2028 | 13 |
| 17 | Thayne Wastewater Lagoon | Thayne | 0.14 | WY0025895 | Jun 2025 | 26 |
| 18 | Saratoga Wastewater Lagoons | Saratoga | 0.14 | WY0021491 | Jan 2029 | 20 |
| 19 | Ranchester Wastewater Lagoons | Ranchester | 0.11 | WY0022161 | Sep 2030 | 13 |
| 20 | Chief Washakie Recreation Comp | Fort Washakie | 0.1 | WYG589101 | Mar 2027 | 84 |
| 21 | Wright Wastewater Treatment | Wright | 0.09 | WY0025992 | Mar 2031 | 0 |
| 22 | Baggs Wastewater Lagoons | Baggs | 0.08 | WY0022888 | Jan 2031 | 598 |
| 23 | Byron Wastewater Lagoon | Byron | 0.07 | WY0020281 | Mar 2029 | 99 |
| 24 | Dubois Wastewater Lagoon | Dubois | 0.06 | WY0020834 | Mar 2029 | 27 |
| 25 | Encampment Wastewater Lagoon | Encampment | 0.05 | WY0020591 | Dec 2026 | 10 |
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 Wyoming
Lagoon systems in other states
Lagoon systems in Wyoming: 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.