The San Francisco Southeast Treatment Plant was built in 1952. The plant expanded several times after it was built. It treats wastewater from the east side of San Francisco, which amounts to about 80 percent of the city s total wastewater flow. The plant is located on Phelps near Third and Evans streets in the Bayview District. It treats an average dry weather flow of about 67 million gallons a day and can treat up to 250 million gallons a day when it rains. Treated wastewater is discharged out an 800-foot-long pipe into the San Francisco Bay.