The Benefits of Post-Construction Warranty Inspections for Long-Term Sanitary Sewer Overflow Control Program Success

Over the past 10 years, the Town of Saugus, Massachusetts (The Town) has experienced several large rain events that have caused significant sanitary sewer overflows (SSOs). Extraneous water entering the sanitary collection system has exceeded the design capacity of the sewer system, forcing the Town to pump excess wastewater directly into the Saugus River in order to protect the Town's main pumping station and its residents. An administrative consent order was issued to the Town by the Massachusetts Department of Environmental Protection (MassDEP) that required an immediate evaluation of the sewer system to assess alternatives and produce a recommended program to control sanitary sewer overflows.A SSO facilities plan evaluated several options to control SSOs. Ultimately, the study recommended comprehensive rehabilitation of nine critical sub-systems over a 10-year period at a cost of $32 million to achieve a 10-year level of control. The plan included complete comprehensive rehabilitation of the public sewer system in these sub-systems, including lining all mainline sewers, service lateral connections from the main to the first joint and lining of all manholes.Due to the extended duration of the project, it was important to ensure predicted performance of the recommended lining rehabilitation measures. To do this, a pilot program was initiated to determine if the rehabilitation products that were specified performed as expected. Post-construction warranty inspections were completed on all lined sewer pipe and manholes prior to the expiration of the contractor's 1-year warranty period to determine the integrity of each installed product and to ensure that they were providing long-term protection from infiltration and inflow.This paper will detail the findings of post-construction warranty inspections, focusing on products used, failure rates, lessons learned and benefits, specifically for long-term construction programs, where consistent, long-lasting solutions are critical to the success of a consent order driven program.