Lagoon systems: wastewater treatment plants in Vermont
26 plants · 34% of the state · 9 MGD combined
Klarifi identifies 26 publicly owned wastewater treatment plants with lagoon systems in Vermont, 34% of the 76 plants in the state (9 MGD combined). The largest is St Albans City in St Albans at 3.2 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 Vermont
| # | Facility | City | Avg flow (MGD) | NPDES permit | Expires | Violations (3y) |
|---|---|---|---|---|---|---|
| 1 | St Albans City | St Albans | 3.2 | VT0100323 | Sep 2022 | 18 |
| 2 | Essex Junction Wastewater Treatment Facility | Essex Junction | 2.07 | VT0100111 | Jun 2026 | 2 |
| 3 | Brattleboro Wastewater Treatment Facility | Brattleboro | 1.28 | VT0100064 | Sep 2021 | 10 |
| 4 | Swanton Village Wastewater Treatment Facility | Swanton | 0.5 | VT0100501 | Jun 2023 | 13 |
| 5 | Waterbury WWTP | Waterbury | 0.35 | VT0100463 | Dec 2025 | 1 |
| 6 | Vergennes WWTF | Vergennes | 0.3 | VT0100404 | Dec 2009 | 82 |
| 7 | Manchester Town Water & Sewer Dept | Manchester | 0.25 | VT0100170 | Sep 2023 | 0 |
| 8 | Proctor Wastewater Treatment Facility | Proctor | 0.21 | VT0100528 | Dec 2027 | 27 |
| 9 | Hinesburg Wastewater Treatment Facility | Hinesburg | 0.16 | VT0101028 | Sep 2028 | 71 |
| 10 | Hardwick Wastewater Treatment Facility | Hardwick | 0.15 | VT0100137 | Jun 2023 | 33 |
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 Vermont
Lagoon systems in other states
Lagoon systems in Vermont: 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 · NPDES permit · MGD · all terms