A private sewer lateral (PSL) is the pipe that carries waste from the plumbing in a home or business to the sanitary sewer main, usually located in the street. It consists of two sections: an upper lateral, which connects the building cleanout to the curbside cleanout, and a lower lateral, which connects the curbside cleanout to the sewer main. Property owners are responsible for maintaining the entire PSL, except in Alameda and Albany where that responsibility is for the upper lateral only.Many East Bay homes were built before 1950, and many have never had their original sewer laterals replaced. Over time, these pipes, which are often made of clay, can crack, become disjointed or be displaced, and can be damaged by tree roots, causing leaks and blockages. When a sewer lateral ages and cracks, it lets rain and ground water into the sewer. This influx of water can overwhelm the treatment plants that clean wastewater, causing partially treated wastewater to be released into the San Francisco Bay. Fixing damaged PSLs helps protect the Bay.