Confirm Whether the Piping Is Polybutylene
Polybutylene, often called PB, is a plastic water-supply piping material found in some existing homes. Accessible pipe may carry a PB or PB2110 marking. Gray piping can be a clue, but color alone cannot distinguish every material.
A copper connection at a sink or water heater does not rule out PB farther along the supply route. Homes can have mixed materials, repairs or remaining sections from an earlier project. Ask a plumber to identify accessible piping and explain which concealed areas remain uncertain.
Polybutylene has a documented history of failure concerns. Its exterior appearance does not establish the condition of the pipe interior. See InterNACHI’s polybutylene identification guidance for background; the next step for your home is an evaluation of the actual system.