All new residential construction that will connect to a sanitary sewer system and any residential construction where the existing sewer connection will be substantially altered shall have a check valve installed, that is automatically activated, on the main building sewer line for purposes of protecting residents from the possible backflow of, and exposure to, untreated sewage.
Mandatory installation of check valves
R.I. Gen. Laws § 23-19.3.1-3., under Chapter 23-19.3.1 Residential Sanitary Sewer Connections.
R.I. Gen. Laws § 23-19.3.1-3.