Lagoon systems: wastewater treatment plants in Wyoming
44 plants · 76% of the state · 16 MGD reported by 31 plants
Klarifi identifies 44 publicly owned wastewater treatment plants with lagoon systems in Wyoming, 76% of the 58 plants in the state (16 MGD reported by 31 plants). The largest is Sam H. Hobbs Regional WW Facility (prev. Casper Wwtf) in Casper at 6.6 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 | Sam H. Hobbs Regional WW Facility (prev. Casper Wwtf) | Casper | 6.6 | WY0021920 | Oct 2030 | 14 |
| 2 | Jackson Wastewater Lagoon | Jackson | 1.93 | WY0021458 | Oct 2029 | 3 |
| 3 | Lander Wastewater Lagoon | Lander | 1.11 | WY0020389 | Apr 2026 | 47 |
| 4 | City Of Rawlins Wastewater Treatment Facility | Rawlins | 0.85 | WY0020427 | Apr 2026 | 6 |
| 5 | Buffalo WWTP | Buffalo | 0.75 | WY0021024 | Oct 2026 | 0 |
| 6 | Green River Wastewater Treatment Plant | Green River | 0.66 | WY0020443 | Jun 2031 | 13 |
| 7 | Basin Wastewater Lagoon | Basin | 0.58 | WY0020028 | Dec 2026 | 35 |
| 8 | Cody Wastewater Lagoon | Cody | 0.54 | WY0020451 | Jan 2030 | 2 |
| 9 | Marbleton Wastewater Lagoon | Marbleton | 0.46 | WY0021997 | Jul 2031 | 155 |
| 10 | Torrington Wastewater Lagoons | Torrington | 0.44 | WY0020231 | Jul 2029 | 18 |
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 October 26, 2026.
Wastewater terms: WWTP · POTW · Biosolids · Anaerobic digester · NPDES permit · all terms