SAN FRANCISCO (CBS SF) – Four homes were declared uninhabitable on Saturday near the spot where a water main broke in San Francisco’s Inner Parkside neighborhood last week, a city 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 SFPUC.
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, 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” and said that may have played a role in the failure.
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.”
She said SFPUC crews planned on going through the neighborhood Monday afternoon to update residents on the ongoing work and investigation into the rupture.
“The geo-tech engineer made it clear that it’s going to take a certain amount of time for the soil to reabsorb this water and essentially re-densify, so that structural work that needs to be done to repair the buildings can be done,” explained Department spokesman Bill Strawn.
“We’re a little concerned about possibly a wet weather front coming in,” he continued.
Building inspectors planned to meet Monday morning to discuss ways to address the problem.
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