"The kids are traumatized. My wife's a nervous wreck. I'm just taking it day by day," one resident said. "It's a big time inconvenience, not just rebuilding the neighborhood. It's not something that's going to happen overnight."
California regulators said Sunday they will order Pacific Gas and Electric -- the company that owns the ruptured pipe -- to survey all its natural gas lines in the state.
As part of the order from the state's Public Utilities Commission, PG&E must run leak surveys on all natural gas lines, with priority given to higher pressure pipelines and to lines in areas of high population density.
The commission also plans to appoint an independent expert panel to help with its investigation.
The pipeline was known to be potentially dangerous. In a 2007 document, PG&E, which owns the line, said the pipeline, "ranks in the top 100 highest risk line sections," adding that the "risk of failure at this location is unacceptably high."
The document was part of a budget request to replace the line.
San Bruno's mayor said he was unaware of the risk assessment.
"The whole thing is troubling to me," Mayor Jim Ruane said.
Investigators from the National Transportation Safety Board took measurements and pictures of pieces of the pipe that exploded, which is the focus of their investigation.
Sunday, the San Mateo County Coroner's Office released the names of three of the at least four people who were killed: Jacqueline Greig, 44, a California Public Utilities Commission employee; her 13-year-old daughter, Janessa Grieg; and 20-year-old Jessica Morales.
The name of the fourth victim has not yet been released, but Faye Wharton told ABC San Francisco station KGO-TV that the body of her 80-year-old grandmother was found in the ruins of her home, which is right next to the explosion.
Wharton told KGO-TV that she received word from authorities late Friday night. She said her two aunts and uncle, who were also in the house, made it out alive, but were severely burned.
Local news reports said residents had attempted to alert Pacific Gas and Electric, the company that operates the pipelines, to the smell of gas days before the explosion.
"We have records that we are going back through right this minute to try and confirm what those phone calls looked like and when they occurred," PG&E president Chris Johns said Friday. Johns said that company policy was to immediately respond if someone calls in with a complaint about the smell of gas.
"We're really saddened and sorry about this tragedy," he said.
Officials from the National Transportation Safety Board are investigating the cause of the blast and will work with PG&E to determine exactly what happened.
"I want to make sure everybody knows that we are committed to do what's right and what's appropriate to help all the families and others who have been impacted by this tragedy," Johns said.
Johns said that no PG&E crews were working in the vicinity during the explosion, but he did not know about any other construction going on. The pipe that ruptured, Johns estimated, was 40 or 50 years old.
ABC affiliate KGO-TV and ABC News' Ariane Nalty, Neal Karlinsky and The Associated Press contributed to this report.