Inflow and Infiltration

Stark Avenue and Downtown Area Sewer Rehabilitation

updated 3/3/2022

Scope of Project

This is a multiphase project to reduce the amount of inflow and infiltration (I/I) from stormwater into the sanitary sewer system. During heavy rain events, I/I can overwhelm the wastewater treatment plant and disrupt the treatment process.

In efforts to reduce I/I, the city contracted with Wright-Pierce to review approximately 125 miles of gravity sewer main within the City of Dover. Flow meters were installed at points in the sewer system to help narrow the locations of high levels of I/I as was the use of smoke testing. The meters registered the downtown area with highest amount of I/I. 

Work is now underway to fix deficiencies found during the review of the sewer system. 

Current work

The City of Dover has contracted with Insituform Technologies, LLC., to rehabilitate sanitary sewer mains in the downtown and Stark Avenue area. These were the areas found to have the highest amount of I/I.

The work includes the trenchless rehabilitation of sewer pipes and maintenance holes in the downtown area and Mill Street area. The specific work includes, but is not limited to:

  • removal of roots, mineral build-up and debris;
  • injection of grouting of cracks and leaking joints;
  • sealing and lining of various maintenance hole components; and
  • epoxy coating of various maintenance hole components.

Rehabilitation includes installing a jointless sewer pipe within sections of the sanitary sewer mains to minimize root and water infiltration problems and to improve flow.

Temporary sewer service disruptions required

To install the jointless sewer pipe, individual sewer services will be temporary sealed from the sewer main. The temporary disruption may last for about 10 hours. The contractor will provide notice to affected properties at least one week in advance.

When the work occurs, please limit water use to avoid discharge backup or damage to the new sewer pipe. Showers are not recommended; if necessary, shut the drain off in the bathtub and leave shower water in the tub until sewer service is restored.

For more information, Community Services at 603-516-6450.