How many wastewater permits expire in New Hampshire in 2026?

28 NPDES permits held by publicly owned wastewater treatment plants in New Hampshire expire in 2026, covering a combined average flow of 12 MGD. The busiest month is Nov 2026 with 21 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 New Hampshire in 2026?

Leavitt E. Magrath Wastewater Treatment Facility in Hampton, treating about 2.08 MGD under permit NH0100625, expiring Feb 2026.

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

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

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New Hampshire wastewater permits expiring in 2026

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

28 NPDES permits · 12 MGD combined average flow

28 publicly owned wastewater treatment plants in New Hampshire hold NPDES permits that expire during 2026, issued by US EPA Region 1 (with NHDES). 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.

All New Hampshire NPDES permits →

Publicly owned wastewater treatment plants in New Hampshire with NPDES permits expiring in 2026, from EPA ICIS-NPDES records. Refreshed on every release.
Facility	City	Avg flow (MGD)	NPDES permit	Expires	Technology	Violations (3y)
Huckleberry Hill Wastewater Treatment Facility	Dover	1.91	NHG58A003	Jan 2026	Clarifiers	30
Exeter Wastewater Treatment Facility	Exeter	1.1	NHG58A004	Jan 2026	Clarifiers, Aerated lagoons	18
Durham Wastewater Treatment Facility	Durham	0.83	NHG58A005	Jan 2026	—	8
Pease Wastewater Treatment Facility	Portsmouth	—	NHG58A007	Jan 2026	Clarifiers	65
Leavitt E. Magrath Wastewater Treatment Facility	Hampton	2.08	NH0100625	Feb 2026	Clarifiers	27
Merrimack WWTF	Merrimack	1.37	NHR053094	Feb 2026	Clarifiers, Biogas silos	9
Lebanon Wastewater Treatment Facility	Lebanon	0.89	NHR053176	Feb 2026	Clarifiers, Biogas balloons	2
Keene Wastewater Treatment Facility	Keene	1.26	NH0100790	Nov 2026	Clarifiers	8
Newmarket, Town Of - WPCF	Newmarket	0.35	NHG580013	Nov 2026	Clarifiers, Biogas silos, Biogas balloons	17
Colebrook Wastewater Treatment Plant	Colebrook	0.3	NHG580315	Nov 2026	—	33
Sunapee, Town Of-WWTP	Sunapee	0.22	NHG580017	Nov 2026	Carrousels / oxidation ditches, Biogas balloons	27
Town Of Bristol WWTF	Bristol	0.21	NHG580021	Nov 2026	Carrousels / oxidation ditches	0
Woodsville Wastewater Treatment Facility	Haverhill	0.18	NHG580978	Nov 2026	—	26
Epping Wasterwater Treatment Facility	Epping	0.13	NHG580012	Nov 2026	Uncovered lagoons	122
Henniker Wastewater Treatment Facility	Henniker	0.11	NHG580018	Nov 2026	Biogas balloons	75
Winchester Wastewater Treatment Plant	Winchester	0.11	NHG580404	Nov 2026	—	1
Newington Wastewater Treatment Plant	Portsmouth (newington)	0.1	NHG581141	Nov 2026	—	82
Whitefield Wastewater Treatment Facility	Whitefield	0.09	NHG580002	Nov 2026	Uncovered lagoons	21
Woodstock WWTF	Woodstock	0.08	NHG580020	Nov 2026	Clarifiers, Carrousels / oxidation ditches	29
Hinsdale Wastewater Treatment Plant	Hinsdale	0.07	NHG580016	Nov 2026	Carrousels / oxidation ditches, Biogas silos	6
W Swanzey WWTF	Swanzey	0.05	NHG580015	Nov 2026	Aerated lagoons	208
Town Of Hopkinton WWTP	Hopkington	0.03	NHG580579	Nov 2026	—	48
Northumberland Village Water Pollution Control Facility	Groveton	0.02	NHG581206	Nov 2026	Aerated lagoons, Uncovered lagoons	22
Stratford Village System	North Stratford	0.02	NHG580536	Nov 2026	—	8
Lisbon Wastewater Treatment Facility	Lisbon	0.02	NHG580421	Nov 2026	Aerated lagoons	25
Cheshire County Maplewood Nursing Home	Westmoreland	0.01	NHG580391	Nov 2026	—	14
Wallis Sands State Park	Rye	0.0021	NHG580014	Nov 2026	—	43
Lancaster Grange Wastewater Treatment Plant	Lancaster	0.0011	NHG581249	Nov 2026	—	3

New Hampshire 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.

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