How many wastewater permits expire in Massachusetts in 2026?

31 NPDES permits held by publicly owned wastewater treatment plants in Massachusetts expire in 2026, covering a combined average flow of 47 MGD. The busiest month is Nov 2026 with 28 expiries.

What happens when an NPDES permit expires?

The plant must have applied for renewal at least 180 days before the expiry date. If the agency has not reissued the permit by then, the old permit is administratively continued and stays enforceable. The reissued permit typically carries updated effluent limits based on the latest water-quality standards, which is what drives upgrade projects.

Which is the largest plant with a permit expiring in Massachusetts in 2026?

Upper Blackstone Wastewater Treatment Plant in Millbury, treating about 30.02 MGD under permit MAR053209, expiring Feb 2026.

How do I get contacts for the plants on this list?

Every plant links to its profile with flow, permit and compliance data. Treatment technology and verified decision-maker contacts for each plant, and the same list for every state and year, are available in Klarifi with a free account.

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Massachusetts wastewater permits expiring in 2026

Name: Massachusetts NPDES permits expiring in 2026
Creator: Klarifi
License: https://klarifi.io/terms-of-service

31 NPDES permits · 47 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.

Other years:

2027 (18)2028 (5)All Massachusetts NPDES permits →

Publicly owned wastewater treatment plants in Massachusetts with NPDES permits expiring in 2026, from EPA ICIS-NPDES records. Refreshed on every release.
Facility	City	Avg flow (MGD)	NPDES permit	Expires	Violations (3y)
Upper Blackstone Wastewater Treatment Plant	Millbury	30.02	MAR053209	Feb 2026	19
Pittsfield Wastewater Treatment Facility	Pittsfield	9.85	MA0101681	Oct 2026	85
Erving Wastewater Treatment Plant #2	Erving	1.77	MA0101052	Nov 2026	36
Manchester Wastewater Treatment Facility	Manchester	0.44	MAG580043	Nov 2026	37
Charlton W W T P	Charlton	0.41	MAG580039	Nov 2026	192
North Brookfield Waste Water Treatment Plant	North Brookfield	0.4	MAG580037	Nov 2026	27
Merrimac Wastewater Treatment Plant	Merrimac	0.36	MAG580030	Nov 2026	0
Hadley Wastewater Treatment Plant	Hadley	0.32	MAG580013	Nov 2026	10
Oxford Rochdale Wastewater Treatment Plant	North Oxford	0.26	MAG580026	Nov 2026	0
Templeton W W T P	Templeton	0.26	MAG580038	Nov 2026	19
M C I Norfolk Walpole	Norfolk	0.21	MAG580036	Nov 2026	5
Cohasset Wastewater Treatment Facility	Cohasset	0.18	MAG580033	Nov 2026	82
Leo L. Dubois WPCF - Bridgewater Correction Complex	Bridgewater	0.17	MAG580040	Nov 2026	42
Stockbridge W W T P	Stockbridge	0.16	MAG580029	Nov 2026	0
Sunderland Wastewater Treatment Facility	Sunderland	0.16	MAG580005	Nov 2026	0
Douglas W W T P	East Douglas	0.15	MAG580006	Nov 2026	132
Hatfield Wastewater Treatment Facility	Hatfield	0.15	MAG580015	Nov 2026	0
Shelburne Wastewater Treatment Facility	Shelburne	0.15	MAG580002	Nov 2026	24
Leicester Water Supply WWTF	Leicester	0.13	MAG580027	Nov 2026	5
Hardwick WPC - Gilbertville	Gilbertville	0.08	MAG580016	Nov 2026	66
Old Deerfield Wastewater Treatment Plant	Deerfield	0.08	MAG580001	Nov 2026	0
Russell Wastewater Treatment Facility	Russell	0.06	MAG580023	Nov 2026	2
Huntington W W T P	Huntington	0.03	MAG580024	Nov 2026	18
Town Of Wayland W W T P	Wayland	0.03	MAG580011	Nov 2026	17
Hardwick WWTP	Hardwick	0.02	MAG580017	Nov 2026	41
West Stockbridge W W T F	West Stockbridge	0.02	MAG580028	Nov 2026	30
Monroe W W T F	Monroe Bridge	0.0095	MAG580019	Nov 2026	8
Royalston Wastewater Treatment Plant	Royalston	0.0067	MAG580020	Nov 2026	71
Woronoco Village W W T F	Woronoco Village	0.0045	MAG580025	Nov 2026	1
Erving POTW #3	Erving	0.0033	MAG580021	Nov 2026	0
Westerly Wastewater Treatment Facility	Marlborough	1.58	MA0100480	Dec 2026	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 October 26, 2026.

Wastewater terms: NPDES permit · POTW · Biological nutrient removal · Tertiary treatment · Ozonation · Activated sludge · all terms

Cite this page

Journalists, researchers and educators are welcome to quote these figures. Please credit Klarifi as the source and link to this page.

Klarifi. “NPDES permits expiring in 2026: Massachusetts plants.” Updated October 26, 2026. https://klarifi.io/facilities/massachusetts/permits-expiring/2026

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