Lagoon systems: wastewater treatment plants in New Jersey
20 plants · 16% of the state · 185 MGD reported by 19 plants
Klarifi identifies 20 publicly owned wastewater treatment plants with lagoon systems in New Jersey, 16% of the 122 plants in the state (185 MGD reported by 19 plants). The largest is Middlesex County Utilities Authority in Sayreville at 77.42 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 New Jersey
| # | Facility | City | Avg flow (MGD) | NPDES permit | Expires | Violations (3y) |
|---|---|---|---|---|---|---|
| 1 | Middlesex County Utilities Authority | Sayreville | 77.42 | NJ0020141 | Jun 2020 | 17 |
| 2 | Bergen County Utilities Authority | Little Ferry | 63.2 | NJ0020028 | Mar 2030 | 176 |
| 3 | Atlantic County Utilities Authority POTW | Atlantic City | 24.52 | NJL024473 | Dec 2030 | 0 |
| 4 | Middletown Twp Slf Belford Section | Middletown | 7.01 | NJ0025356 | Dec 2025 | 4 |
| 5 | Cape May Cnty MUA 7 Mile Beach Middle Rgnl Wtf | Cape May Court House | 2.88 | NJ0052990 | Jun 2026 | 2 |
| 6 | East Windsor Water Pollution Control Plant | East Windsor | 2.38 | NJ0023787 | Mar 2027 | 86 |
| 7 | Molitor Water Pollution Control Facility | Chatham | 1.91 | NJ0024937 | Dec 2029 | 170 |
| 8 | Logan Township MUA | Bridgeport | 1.46 | NJ0027545 | Sep 2028 | 2 |
| 9 | Harrison Brook STP | Liberty Corner | 1.29 | NJ0022845 | Mar 2027 | 6 |
| 10 | Chatham Twp DPW Main STP Water Pollution Control Plant | Chatham | 0.71 | NJ0020290 | Dec 2030 | 64 |
| 11 | Newton Town DPW | Newton | 0.61 | NJ0020184 | Mar 2023 | 50 |
| 12 | Readington Lebanon Sewer Auth | Whitehouse | 0.58 | NJ0098922 | Jun 2029 | 30 |
| 13 | Beverly Sewerage Authority | Beverly | 0.44 | NJ0027481 | Jun 2028 | 66 |
| 14 | Warren Twp Sewer Auth Stage 4 WWTP | Warren | 0.39 | NJ0022497 | Sep 2030 | 16 |
| 15 | Buena Borough MUA Cs-Septics | Buena | 0.27 | NJ0021717 | Mar 2025 | 0 |
| 16 | Riverton STP | Riverton | 0.12 | NJ0021610 | Dec 2028 | 27 |
| 17 | Warren Twp Sewer Auth Stage 5 STP | Warren | 0.09 | NJ0050369 | Jun 2025 | 8 |
| 18 | Mercer County Correction Ctr WTP | Hopewell Twp | 0.06 | NJ0027715 | Sep 2024 | 31 |
| 19 | Hancocks Bridge STP | Hancocks Bridge | 0.02 | NJ0050423 | Dec 2024 | 201 |
| 20 | Cloverhill STP | Flanders | — | NJ0021954 | Dec 2029 | 72 |
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 New Jersey
Lagoon systems in other states
Lagoon systems in New Jersey: 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.