Four homes were declared uninhabitable Saturday near the spot where a water main broke in the West Portal neighborhood last week, a San Francisco Public Utilities Commission spokeswoman said Monday.
The 16-inch, cast-iron pipe ruptured shortly after 2:30 a.m. Wednesday on 15th Avenue just south of Wawona Street, sending water and mud down the hill and damaging 23 homes and 12 vehicles, according to the agency.
Several homes were yellow-tagged that day, meaning they still had limited areas that were habitable, but over the weekend four were changed to red tags and the residents had to vacate the homes, SFPUC spokeswoman Allison Kastama said.
One of the homes was red-tagged because the adjacent sewer system had collapsed, cutting off sewer service to the home, Kastama said. The other three were declared uninhabitable because of concerns about the stability of the foundations at the back of the homes, she said.
The four homes are located on 15th Avenue between Wawona and Vicente streets.
Temporary housing is being provided for the displaced residents, Kastama said.
A large sinkhole that opened up at the site of the initial water main break has been repaired, and the SFPUC and other city departments are working with residents whose property was damaged.
The cause of the rupture remains under investigation, Kastama said. She said the pipe was located in an old creekbed where “soil conditions are not ideal.” Some residents speculated that recent sewer work in the area may have caused the break, but Kastama said, “It’s unclear if that’s related.”