Lagoon systems: wastewater treatment plants in Pennsylvania
149 plants · 19% of the state · 69 MGD reported by 146 plants
Klarifi identifies 149 publicly owned wastewater treatment plants with lagoon systems in Pennsylvania, 19% of the 783 plants in the state (69 MGD reported by 146 plants). The largest is Springettsbury Wastewater Treatment Plant in York at 7.61 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 Pennsylvania
| # | Facility | City | Avg flow (MGD) | NPDES permit | Expires | Violations (3y) |
|---|---|---|---|---|---|---|
| 1 | Springettsbury Wastewater Treatment Plant | York | 7.61 | PAL026808 | Dec 2030 | 4 |
| 2 | Indiana Boro WWTP | Indiana | 3.43 | PA0026751 | Jun 2031 | 0 |
| 3 | Clairton Mun Auth STP | Clairton | 3.42 | PAL026824 | Dec 2030 | 19 |
| 4 | West Goshen Township WWTP | West Chester | 3.12 | PAL028584 | Dec 2030 | 2 |
| 5 | Altoona Easterly STP | Altoona | 2.82 | PA0027014 | Sep 2026 | 5 |
| 6 | Hermitage Muni Auth STP | Hermitage | 2.42 | PAL028487 | Dec 2030 | 1 |
| 7 | Shippensburg STP | Shippensburg | 2.35 | PA0030643 | Aug 2028 | 2 |
| 8 | Upper Gwynedd Twp STP | North Wales | 2.21 | PAL023256 | Dec 2030 | 36 |
| 9 | Sunbury Muni Auth STP | Sunbury | 1.75 | PAL026557 | Dec 2030 | 2 |
| 10 | Quakertown WWTP | Quakertown | 1.68 | PAL020290 | Dec 2030 | 35 |
| 11 | City Of Dubois Sewage Treatment Plant | Dubois | 1.63 | PA0027375 | Nov 2025 | 48 |
| 12 | Ingleside STP | Johnstown | 1.4 | PA0026778 | Apr 2026 | 2 |
| 13 | Northeast Boro STP | North East | 1.36 | PAL023043 | Dec 2030 | 7 |
| 14 | Clearfield Mun Sew Sys STP | Clearfield | 1.13 | PA0026310 | Feb 2028 | 1 |
| 15 | Harvey Avenue STP | Doylestown | 1.1 | PA0021172 | Apr 2027 | 0 |
| 16 | Grove City Boro STP | Grove City | 1.05 | PA0020257 | Oct 2030 | 0 |
| 17 | Valley Jt Sew Auth STP | Athens | 1 | PA0043681 | May 2028 | 0 |
| 18 | Myerstown STP | Myerstown | 0.97 | PA0021075 | Mar 2026 | 0 |
| 19 | Bangor Wastewater Treatment P | Bangor | 0.9 | PAL028568 | Dec 2030 | 10 |
| 20 | Franklin Wastewater Treatment Plant | Franklin | 0.85 | PAL026174 | Dec 2030 | 0 |
| 21 | Lewisburg Area Jt. Sewer Auth | Lewisburg | 0.84 | PAL044661 | Dec 2030 | 1 |
| 22 | Nazareth Boro Muni Auth WWTP | Nazareth | 0.84 | PA0041742 | Apr 2024 | 1 |
| 23 | New Holland WWTP | New Holland | 0.78 | PAL021890 | Dec 2030 | 23 |
| 24 | Mt Joy Boro Auth | Mount Joy | 0.76 | PA0021067 | May 2031 | 2 |
| 25 | West Mifflin - Thompson Run STP | West Mifflin | 0.74 | PA0026506 | Mar 2025 | 55 |
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 Pennsylvania
Lagoon systems in other states
Lagoon systems in Pennsylvania: 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.