Henniker Wastewater Treatment Facility
Henniker, NH · Merrimack County · Publicly Owned Treatment Works
- Average flow
- 0.11 MGD
- Design flow
- —
- NPDES permit
- NHG580018
- Effective
- Permit expires
- November 2026
- Population served
- 1,850
- CWNS 2022
Henniker Wastewater Treatment Facility is a publicly owned wastewater treatment works in Henniker, Merrimack County, New Hampshire treating an average of 0.11 million gallons per day, serving about 1,850 residents. Treatment on site includes biogas balloons. It discharges under NPDES permit NHG580018 (effective), which expires in November 2026, with 75 recorded violations in the last three years.
Treatment technology
Treatment structures identified at this facility. Exact unit counts are available in Klarifi.
Biogas balloons
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Compliance snapshot (last 3 years)
- Total violations
- 75
- Effluent violations
- 34
Based on NPDES Discharge Monitoring Reports. Full violation history, parameters and discharge data available in the Klarifi platform.
Key contacts
1 verified contact for Henniker Wastewater Treatment Facility, with validated emails and direct phone numbers.
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Names, validated emails and direct phone numbers for decision-makers at Henniker Wastewater Treatment Facility, plus the full compliance history and discharge data.
Nearby wastewater treatment plants in New Hampshire
Hopkington · 7 mi away
0.03 MGD
Concord · 14 mi away
0.18 MGD
Concord · 15 mi away
3.2 MGD
Allenstown · 18 mi away
0.45 MGD
Franklin · 18 mi away
3.53 MGD
Hooksett · 19 mi away
0.68 MGD
Sunapee · 21 mi away
0.22 MGD
Milford · 26 mi away
0.78 MGD
Henniker Wastewater Treatment Facility: frequently asked 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; facility record last updated November 28, 2025.