Surface Water Treatment Plant

The town's Surface Water Treatment Plant (SWTP), located at 109 Portsmouth Avenue, provides a large portion of Exeter's potable water.  The other main public water supply comes from the groundwater treatment plant (GWTP) located on Lary Lane.

The waterworks facilities at the Portsmouth Avenue site date back to 1886, and were privately owned and operated by the Exeter Waterworks.  The Waterworks sold the assets of the plant and supply to the town in 1950. The last major upgrades to the surface water treatment plant took place in 1993-94.

The SWTP receives raw water from the Exeter Reservoir, Exeter River (via a pump station located adjacent to Gilman Park), and Skinner Springs (located in Stratham). The Exeter River is the main source of water from mid-spring through mid-autumn. The reservoir behind the main surface water treatment plant facility typically supplies the plant during the remaining months of the year, however, water is pumped from the Exeter River to the Exeter Reservoir during the winter necessary to maintain adequate levels in the reservoir.  The operation of the new groundwater plant on Lary Lane, along with the removal of the Great Dam, is expected 

The plant operates on 18 hours per day max - less on weekends, but more during fire hydrant flushing. The WTP objective at the beginning of each day is to fill the distribution system storage tanks, which are typically depleted throughout the night while the WTP is off-line.  Aging equipment and facilities present increasing operational difficulties. A very high percentage of raw water is lost due to the clarification process, which affects the WTP and the Wastewater Treatment Plant (WWTP). A water system evaluation (CDM 2002), recommended a new water treatment plant as highest priority for improvements to the Town's water system.

Several projects are required to keep the existing plant operational and in compliance with ever changing regulations.

Groups interested in tours of the Water Treatment Plant can contact the operators directly for details (603) 773 - 6169. 

Water Treatment Plant Receives Recognition ~ 2012

On November 8, 2012 the State of New Hampshire Department of Environmental Services (NHDES) Water Division, awarded the Exeter Water Department for Surface Water Treatment Optimization. During the first half of 2011 several NHDES officials attended a workshop presented by the Environmental Protection Agency (EPA) on the “Partnership for Safe Water.” The State of Pennsylvania followed-up and sponsored an “Area Wide Optimization Program” which was introduced at the workshop. Surface Water Treatment Plants in Pennsylvania were having difficulty meeting EPA regulations for maximum turbidity in the effluent waters of 0.3 NTU (Nephelometric Turbidity Units) from the facilities, and challenged them to get down to a consistent 0.1 NTU.

From September 1, 2011 through August 31, 2012 the NHDES officials monitored the monthly reports from 20 New Hampshire surface water treatment facilities to verify the optimization of 0.1 NTU maximum in treated drinking water. The Town of Exeter Surface Water Treatment Plant is proud to be one of the six (6) facilities that met these requirements.