783 facilities · 715 MGD combined flow
Klarifi tracks 783 publicly owned wastewater treatment plants in Pennsylvania with a combined average flow of 715 MGD, serving about 1,779,527 residents. 104 plants treat more than 1 MGD and 7 more than 10 MGD; 149 use lagoon systems and 94 have digesters or biogas infrastructure. The largest is Allegheny Cnty Sani Auth/allegheny Cnty in Pittsburgh at 152.8 MGD. 95 NPDES permits expire this year and 109 next year.
Every plant below links to a profile with average and design flow, treatment technology, the NPDES permit and its expiry, a three-year compliance snapshot and the capital projects planned in its city. Showing facilities 1–200 of 783 by average flow — browse the rest with the page links below.
783 plant locations in Pennsylvania; dot size follows average flow.
Every plant discharges under an NPDES permit that is renewed every five years, usually with tighter limits. The renewal year is the year a plant budgets for upgrades.
| Facility | City | Avg flow (MGD) | Design (MGD) | NPDES permit | Expires | Technology | Violations (3y) |
|---|---|---|---|---|---|---|---|
| Allegheny Cnty Sani Auth/allegheny Cnty | Pittsburgh | 152.8 | — | PAL025984 | Dec 2030 | — | 1 |
| Phila Water Dept - SE STP | Philadelphia | 77 | — | PAL026662 | Dec 2030 | — | 1 |
| City Of Allentown Wastewater Treatment Plant | Allentown | 31.07 | 40 | PA0026000 | Sep 2007 | Clarifiers, Carrousels / oxidation ditches, Biogas silos, Biogas balloons | 0 |
| Delcora-Western Regional Treatment Plant | Chester | 27.54 | 44 | PA0027103 | Mar 2026 | Clarifiers | 18 |
| City Of Erie, Pa - Wastewater Treatment Plant | Erie | 24.1 | — | PAL026301 | Dec 2030 | Clarifiers | 1 |
| Wyoming Valley Sani Auth Wilkes Barre | Wilkes Barre | 17.3 | — | PAL026107 | Dec 2030 | Clarifiers, Carrousels / oxidation ditches | 1 |
| Reading STP | Reading | 14.09 | 20.5 | PA0026549 | Apr 2028 | Clarifiers, Carrousels / oxidation ditches, Biogas silos, Biogas balloons | 9 |
| City Of Bethlehem Wastewater Treatment Plant | Bethlehem | 9.97 | 40 | PA0026042 | May 2031 | Clarifiers, Biogas silos, Biogas balloons | 18 |
| Springettsbury Wastewater Treatment Plant | York | 7.61 | — | PAL026808 | Dec 2030 | Clarifiers, Aerated lagoons, Biogas silos | 4 |
| Lrbsa - Throop Plant | Throop | 5.7 | 10 | PA0027090 | Aug 2021 | Clarifiers, Biogas balloons | 6 |
| Oaks WWTP (lower Perkiomen Valley) | Oaks | 5.54 | 14.25 | PA0026964 | Nov 2030 | Clarifiers, Biogas silos | 5 |
| Lower Bucks WWTP | Levittown | 5.34 | 10 | PA0026468 | May 2028 | Clarifiers, Biogas silos | 25 |
| Lebanon City STP | Lebanon | 5.22 | — | PAL027316 | Dec 2030 | Clarifiers, Biogas silos, Biogas balloons | 1 |
| Chambersburg Boro STP | Chambersburg | 5.16 | — | PAL026051 | Dec 2030 | Clarifiers, Biogas silos | 0 |
| Gr Hazleton Jt Sew Auth WWTP | Hazleton | 5.15 | 8.9 | PA0026921 | Feb 2027 | Clarifiers, Biogas silos | 6 |
| Valley Forge Sewer Authority WWTP | Phoenixville | 4.66 | — | PAL043974 | Dec 2030 | Clarifiers, Biogas silos | 8 |
| Washington E Washington STP | Washington | 4.51 | 9.77 | PA0026212 | Jan 2031 | Clarifiers, Biogas silos | 174 |
| Lower Allen Twp STP | New Cumberland | 4.33 | — | PAL027189 | Dec 2030 | Clarifiers, Biogas silos, Biogas balloons | 0 |
| Upper Allegheny Jt Sani Auth STP | Creighton | 4.3 | 9 | PA0027391 | Aug 2015 | — | 0 |
| Uniontown STP | Uniontown | 4.2 | 9.4 | PA0027219 | Jul 2027 | Clarifiers, Biogas silos | 6 |
| Norristown Muni STP | Norristown | 3.96 | 9.75 | PA0027421 | May 2029 | Clarifiers, Biogas silos | 2 |
| Log College STP | Warminster | 3.78 | 8.93 | PA0026166 | Aug 2026 | Clarifiers, Biogas silos | 7 |
| Upper Moreland Hatboro Jt Sew Auth/willow Grove | Willow Grove | 3.68 | — | PAL025976 | Dec 2030 | Biogas silos | 20 |
| Hanover Boro STP | Mcsherrystown | 3.65 | 17.6 | PA0026875 | Dec 2027 | Clarifiers, Carrousels / oxidation ditches, Biogas silos | 2 |
| E Norriton Plymouth /norristown | Plymouth Meeting | 3.6 | — | PAL026816 | Dec 2030 | Clarifiers, Biogas silos | 7 |
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.