San Francisco city officials threw a party at a school gym in Visitacion Valley last Saturday to celebrate a return to normalcy after a yearlong sewer project wrapped up on Sunnydale Avenue.

Three days later, the neighborhood was back in turmoil after a large water main broke, flooding homes, cars and a school campus — including the gym where the party was held.

The 42-inch pipe ruptured about 11:10 a.m. Tuesday on Sunnydale Avenue between Cora Street and Tomaso Court, prompting the evacuation of 14 homes and the nearby Our Lady of the Visitacion School. The break left a gaping hole in the street several feet deep.

Joseph Moreno, 42, was one of a number of residents who were initially displaced but were allowed to return home Wednesday.

Moreno, who has lived in the neighborhood for about 30 years, said that while some of his neighbors had flood damage, his family’s house was intact. He said that although he and his family have been able to move back in, his home still does not have hot water.

“I took the coldest shower ever in my house this morning,” Moreno said. “It’s been rough.”

He said neighbors have been wondering whether the rupture of the water main was connected to the sewer project, which had caused Sunnydale Avenue to be reduced to one-way traffic for at least a year.

“It’s a coincidence that they just finished the road,” he said.

San Francisco Public Utilities Commission spokesman Tyrone Jue said the end of the sewer project and the main break are not connected. “They’re completely unrelated, not even in the same vicinity,” Jue said.

He said the cause of the rupture remains under investigation. Jue said it could take as long as three weeks to bring in a replacement pipe and repair the roadway.