Massachusetts wastewater permits expiring in 2026
31 NPDES permits · 38 MGD combined average flow
31 publicly owned wastewater treatment plants in Massachusetts hold NPDES permits that expire during 2026, issued by US EPA Region 1 (with MassDEP). The table lists each plant with its permit number, expiry month, average flow, treatment technology and three-year violation count, in order of expiry.
An NPDES permit runs for five years. To keep discharging, a plant must apply for renewal at least 180 days before the expiry date, and the renewed permit usually arrives with tighter effluent limits, new monitoring requirements or a compliance schedule. That is why the year a permit expires is the year a plant starts budgeting for upgrades: nutrient removal, disinfection, capacity or controls.
| Facility | City | Avg flow (MGD) | NPDES permit | Expires | Technology | Violations (3y) |
|---|---|---|---|---|---|---|
| Upper Blackstone Wastewater Treatment Plant | Millbury | 24.1 | MAR053209 | Feb 2026 | Clarifiers | 15 |
| Pittsfield Wastewater Treatment Facility | Pittsfield | 7 | MA0101681 | Oct 2026 | Clarifiers, Carrousels / oxidation ditches, Biogas silos, Biogas balloons | 84 |
| Erving Wastewater Treatment Plant #2 | Erving | 1.72 | MA0101052 | Nov 2026 | Clarifiers, Aerated lagoons, Biogas balloons | 36 |
| Hardwick WPC - Gilbertville | Gilbertville | 0.44 | MAG580016 | Nov 2026 | Clarifiers | 31 |
| Hadley Wastewater Treatment Plant | Hadley | 0.34 | MAG580013 | Nov 2026 | Clarifiers | 6 |
| Charlton W W T P | Charlton | 0.31 | MAG580039 | Nov 2026 | Clarifiers | 129 |
| North Brookfield Waste Water Treatment Plant | North Brookfield | 0.29 | MAG580037 | Nov 2026 | Clarifiers | 20 |
| Manchester Wastewater Treatment Facility | Manchester | 0.29 | MAG580043 | Nov 2026 | Clarifiers | 33 |
| Merrimac Wastewater Treatment Plant | Merrimac | 0.28 | MAG580030 | Nov 2026 | Clarifiers, Carrousels / oxidation ditches | 0 |
| Cohasset Wastewater Treatment Facility | Cohasset | 0.21 | MAG580033 | Nov 2026 | — | 66 |
| Templeton W W T P | Templeton | 0.2 | MAG580038 | Nov 2026 | Aerated lagoons | 19 |
| M C I Norfolk Walpole | Norfolk | 0.18 | MAG580036 | Nov 2026 | Clarifiers | 4 |
| Oxford Rochdale Wastewater Treatment Plant | North Oxford | 0.17 | MAG580026 | Nov 2026 | Clarifiers, Uncovered lagoons | 0 |
| Leo L. Dubois WPCF - Bridgewater Correction Complex | Bridgewater | 0.15 | MAG580040 | Nov 2026 | Clarifiers, Uncovered lagoons, Carrousels / oxidation ditches | 40 |
| Hatfield Wastewater Treatment Facility | Hatfield | 0.14 | MAG580015 | Nov 2026 | — | 0 |
| Sunderland Wastewater Treatment Facility | Sunderland | 0.13 | MAG580005 | Nov 2026 | Clarifiers | 0 |
| Douglas W W T P | East Douglas | 0.13 | MAG580006 | Nov 2026 | — | 132 |
| Shelburne Wastewater Treatment Facility | Shelburne | 0.11 | MAG580002 | Nov 2026 | — | 24 |
| Stockbridge W W T P | Stockbridge | 0.1 | MAG580029 | Nov 2026 | Clarifiers, Carrousels / oxidation ditches | 0 |
| Leicester Water Supply WWTF | Leicester | 0.09 | MAG580027 | Nov 2026 | Clarifiers, Aerated lagoons | 5 |
| Old Deerfield Wastewater Treatment Plant | Deerfield | 0.07 | MAG580001 | Nov 2026 | — | 0 |
| Russell Wastewater Treatment Facility | Russell | 0.04 | MAG580023 | Nov 2026 | Carrousels / oxidation ditches | 2 |
| Town Of Wayland W W T P | Wayland | 0.03 | MAG580011 | Nov 2026 | — | 17 |
| Huntington W W T P | Huntington | 0.03 | MAG580024 | Nov 2026 | — | 19 |
| Hardwick WWTP | Hardwick | 0.01 | MAG580017 | Nov 2026 | — | 14 |
| West Stockbridge W W T F | West Stockbridge | 0.009 | MAG580028 | Nov 2026 | — | 32 |
| Woronoco Village W W T F | Woronoco Village | 0.004 | MAG580025 | Nov 2026 | — | 2 |
| Royalston Wastewater Treatment Plant | Royalston | 0.0035 | MAG580020 | Nov 2026 | — | 71 |
| Erving POTW #3 | Erving | 0.0027 | MAG580021 | Nov 2026 | — | 0 |
| Monroe W W T F | Monroe Bridge | 0.0027 | MAG580019 | Nov 2026 | — | 8 |
| Westerly Wastewater Treatment Facility | Marlborough | 1.16 | MA0100480 | Dec 2026 | Clarifiers | 26 |
Massachusetts permit renewals in 2026: 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.