Newington operates a secondary wastewater treatment facility which serves the town's sewer district commercial and industrial districts. The plant is located behind Portsmouth Chevrolet, just north of Gosling Road.

The facility was built between 1979 and 1981. The plant's operations and finances are overseen by a three member Sewer Commission.

The Town contracts with the Earthtech Corporation to operate the facility. The town is well served in this manner by plant operator Denis Messier and his able assistant F. Jackson Hoyt.

In order to connect to the system, a permit is required from the Sewer Commission. Sewer District regulations must also be adhered to.

Plant operators may be contacted at 603-431-4111, or via email.