Lagoon systems: wastewater treatment plants in Michigan
172 plants · 51% of the state · 240 MGD reported by 142 plants
Klarifi identifies 172 publicly owned wastewater treatment plants with lagoon systems in Michigan, 51% of the 334 plants in the state (240 MGD reported by 142 plants). The largest is City Of Grand Rapids Wastewater Treatment Plant in Grand Rapids at 42.18 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 Michigan
| # | Facility | City | Avg flow (MGD) | NPDES permit | Expires | Violations (3y) |
|---|---|---|---|---|---|---|
| 1 | City Of Grand Rapids Wastewater Treatment Plant | Grand Rapids | 42.18 | MI0026069 | Oct 2029 | 9 |
| 2 | City Of Saginaw Wastewater Treatment Plant | Saginaw | 34.99 | MI0025577 | Oct 2029 | 21 |
| 3 | Clinton River WRRF | Pontiac | 14.29 | MI0023825 | Oct 2030 | 3 |
| 4 | Jackson WWTP | Jackson | 11.39 | MI0023256 | Oct 2027 | 4 |
| 5 | Saginaw Twp WWTP | Saginaw | 5.22 | MI0023973 | Oct 2028 | 10 |
| 6 | Cbpu Waste Water Treatment Plant | Coldwater | 3.54 | MI0020117 | Oct 2026 | 10 |
| 7 | Sault Ste. Marie Wastewater Treatment Plant | Sault Sainte Marie | 3.04 | MI0024058 | Oct 2025 | 24 |
| 8 | Baraga Wwsl | Baraga | 2.91 | MIG580400 | Apr 2029 | 34 |
| 9 | Bangor Wwsl | Bangor | 2.62 | MIG580286 | Apr 2024 | 7 |
| 10 | Ithaca Wwsl | Ithaca | 2.58 | MI0056928 | Oct 2026 | 35 |
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 Michigan
Lagoon systems in other states
Lagoon systems in Michigan: 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 · Biological nutrient removal · Tertiary treatment · all terms