Lagoon systems: wastewater treatment plants in North Dakota
196 plants · 98% of the state · 42 MGD reported by 11 plants
Klarifi identifies 196 publicly owned wastewater treatment plants with lagoon systems in North Dakota, 98% of the 200 plants in the state (42 MGD reported by 11 plants). The largest is Grand Forks City Of in Grand Forks at 12.26 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 North Dakota
| # | Facility | City | Avg flow (MGD) | NPDES permit | Expires | Violations (3y) |
|---|---|---|---|---|---|---|
| 1 | Grand Forks City Of | Grand Forks | 12.26 | ND0022888 | Dec 2028 | 7 |
| 2 | Bismarck City Of (potw) | Bismarck | 7.34 | ND0023434 | Jun 2028 | 0 |
| 3 | City Of Minot - Minot Landfill | Minot | 5.03 | ND0022896 | Mar 2030 | 20 |
| 4 | West Fargo City Of | West Fargo | 5 | ND0022616 | Sep 2029 | 4 |
| 5 | Devils Lake City Of | Devils Lake | 3.8 | ND0020681 | Mar 2028 | 77 |
| 6 | Williston City Of | Williston | 2.86 | ND0022349 | Mar 2028 | 4 |
| 7 | New Town Water Resource Recovery Facility | New Town | 2.3 | NDG589108 | Mar 2027 | 1 |
| 8 | Mandan Landfill / Ts | Mandan | 1.69 | ND0022861 | Sep 2031 | 0 |
| 9 | Medora City Of | Medora | 0.68 | ND0022799 | Jun 2031 | 4 |
| 10 | Watford City City Of | Watford City | 0.64 | ND0021849 | Sep 2030 | 27 |
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.
Lagoon systems in other states
Lagoon systems in North Dakota: 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 · MGD · Lift station · all terms