Wastewater Treatment & Sewer Collection

Concord General Services Wastewater Treatment Division and Highway and Utilities Division provide services for the collection and treatment of wastewater (PDF) for Concord and portions of Bow and Boscawen. The wastewater collection system contains 163 miles of sanitary sewer line and 8 pump stations throughout Concord. Two wastewater treatment facilities treat the City’s wastewater.

Report A Concern

Use our request tracker to report a concern about the sewer or wastewater odor.

World Water Day - Facility Tour

March 22, 2019 is World Water Day, a United Nations initiative to celebrate water and advocate for sustainable management of resources. The City of Concord invites the community to get involved by learning more about wastewater. Wastewater is used water. It’s the water after you wash your hands, brush your teeth, take a shower, do laundry, wash dishes, or flush the toilet. Where does the water go after it's used? For developing countries and low-income areas, wastewater is often directly discharged into the closest surface water drain with very little to no treatment. Approximately 80% of wastewater worldwide flows back into nature without being treated or reused. For Concord, wastewater is collected through the City's sanitary sewer collection system and transported to one of our wastewater treatment facilities. Approximately 4.3 million gallons of wastewater are processed every day in Concord to protect public health and the local environment. The reclaimed water is properly disinfected, tested regularly for quality standards, and recovered safely back into the Merrimack River. The City’s investments in sustainable wastewater management, including building our treatment facilities in 1973 and 1979, have since improved the quality of the Merrimack River. 

Open House - Hall Street Wastewater Treatment Facility

In celebration of World Water Day, Concord residents are invited to attend an open house of our Hall Street Wastewater Treatment Facility on March 22nd. Visit the administration building at 125 Hall Street any time between 11:00 a.m. and 1:00 p.m. for a facility tour and a walk-through of the treatment process. Attendees should be advised that odor emissions have reduced significantly over the years through past facility improvements, but some odors are still present due to the natural treatment process. For any questions about the open house, please send an email to generalservices@concordnh.gov. We hope to see you there!

Hall Street Wastewater Treatment Facility

The main wastewater treatment facility is located at 125 Hall Street in Concord. The facility was built in 1979 and provides wastewater treatment for Concord and portions of Bow. The plant was designed for a capacity of 10.1 million gallons per day and a peak flow capacity of 25.0 million gallons. The plant is currently treating an average of 4 million gallons of wastewater per day. The facility also treats various off-site waste streams, including approximately 5 million gallons of landfill leachate per year and 2 million gallons of domestic septage from local communities. The plant process generates approximately 7,500 wet tons of biosolids annually that are transported off-site to be used as fertilizer or as a component of manufactured topsoil. The facility occupies approximately 28 acres of land, although the City of Concord owns an additional 75 acres around the plant that consists of wooded areas and farm land. Read our feature in the Summer 2017 issue of the NEWEA Journal to see the future options of biosolid stabilization in Concord.

Penacook Wastewater Treatment Facility

The Penacook Wastewater Treatment Plant is located at 7 Penacook Street in Penacook. The plant was originally built in 1973 to treat a significant industrial discharge from the former Allied Leather Tannery. After the tannery closed in 1987, the flow reduced. The plant was converted from a conventional activated sludge plant to a sequencing batch reactor (SBR) process in 2005 after flow conditions were below the capacity. This facility treats an average of 300,000 gallons of wastewater per day and has a treatment capacity of 1.2 million gallons. The former primary clarifier and aeration tank is utilized for wastewater storage during periods of high flow, which occur primarily during the early spring of each year. This facility services the Penacook area of Concord and a portion of Boscawen. Concord is one of two communities (the other being Portsmouth) in New Hampshire that operate two wastewater treatment facilities. Read our feature in the September 2016 issue of TPO Magazine (PDF) for more information about our Penacook Wastewater Treatment Facility.