Friends of Mission Creek:

History of San Francisco’s Sewers

San Francisco’s sewer system dates back to the 1850s, the earliest days of urban development on the US West Coast. San Francisco’s system was originally a hodge-podge of sewers installed somewhat haphazardly at first, then with much gusto for trying to improve urban drainage in the 1860s and 1870s. During that time, most of the sewers built were “3x5” brick sewers all interconnected on San Francisco’s infamous hills, leading to the bottom of the hills where they transitioned to large redwood boxes that were essentially septic tanks, discharging into the bay where each street ended. Initially these sewers primarily served the purpose of roadway drainage, draining the corner catch basins and leading the rain water and the pollution of the day, horse manure, away.

In the earliest days, water was scarce and only a few well founded homes had indoor plumbing. With improvements to the water supply, leading to the replacement of privy based sanitation with water based indoor plumbing, SF’s sewers soon become septic nightmares with the City residents frequently demanding improvements to the noxious nuisances.In the 1870s city fathers requested engineering help which came in the form of several large intercepting sewers being placed in the creek beds which were then covered up, moving the wastes from the commercial centers towards the marshy areas at the bay or along the docks of the waterfront. There was also an initial attempt at standardizing the sizes of sewers with smaller sewers upstream and larger sewers downstream. This effort only led to a few areas being improved however.

By the 1890s there was a growing demand for a more comprehensive approach to urban sewerage. In came C.E. Grunsky, who after working in SF went on to be a famous engineer of western water and the Panama Canal. Grunsky’s solution was a gravity based  system of smaller interceptors leading to 2 large sanitary interceptor sewers which conveyed the sanitary portion of the sewage to 2 outfalls along the northern waterfront where the tides of the Golden Gate would help disperse the effluent of the growing city. At strategic points side weirs would allow excessive rainfall in the system to overflow from these sewers down to outfalls along the bay. This system was started after the 1906 earthquake and although substantially completed by 1918, parts were delayed by WWI and not completed until the late 1920s.

The system carried sanitary wastes from approx. 85% of the city that was above the 2 large interceptors and envisioned pumps to carry the sanitary wastes from portions of the City below the interceptors to them. It also envisioned the possibility of flow through sewage treatment but these concepts were not fully implemented until another “master plan” effort was done in the 1930s which promoted the building of 3 primary sewage treatment plants on each side of the City. Construction was started during the late 1930s with WPA assistance but was put on hold during WWII with the construction of the plants completed in the early 1950s and the rest of the system being built out and completed by 1963.

San Francisco was one of the earliest cities required to address its CSO pollution soon after the passage of the Clean Water Act in the 1970s. SF officials complained vigorously and resisted any attempt to address these requirements. From 1974 to 1994 it had several Cease and Desist Orders (CDO) against it with court injunctions leading judges to impose "building bans" if the City continued to stall and not address its pollution. With the help of substantial Federal grants, and state and federal low interest loans, SF worked to compromise with state and federal regulators and started a "Clean Water Program" (CWP) to design and build the improvements required to meet the CDOs.

This Page: History of SF Sewers