In early February, the Department of Public Utilities (DPU) sent a letter to 2,438 customers with a potential risk of sewer backups, encouraging them to install backwater valves if their system was lacking one.
DPU began investigating after finding that four homes that experienced sewer backups should have been equipped with backwater valves. Only one was, and that one was not functioning properly.
A topographical survey was used to determine which sites could be at risk by being below grade of the nearest upstream manhole. DPU estimates that an average of five homes a year experience sewage backups that could have been prevented with backwater valves.