A water main break at La Entrada Middle School in Menlo Park on Thursday, Nov. 29, flooded the campus for the second time in five weeks, leading officials to cancel classes.

The Menlo Park Municipal Water Department is working to fix the break, water systems supervisor Luis Olivera wrote in an email Thursday.

The flooding began after a water main broke at the city/school connection point, Las Lomitas Elementary School District Superintendent Lisa Cesario said in an email. The district did not say what time the main broke.

Officials dismissed students around 12:45 p.m. because all water was shut off, cutting off students' access to bathrooms, she wrote. School resumed on Friday, Nov. 30, with port-a-potties and bottled water provided to students, said Menlo Park City Councilman Ray Mueller. Water leaked into four classrooms and officials are relocating classroom materials to other spaces on campus.

The water department worked on repairs during the day on Thursday, but as it continued raining, a second break occurred in the evening, said Mueller. At this point, California Water Service stepped in to help, he said. The affected pipes also run through private property, which has added some complexity to the repair process, he said.

"They're really doing the best they can to get this thing repaired," he said.

The district is assessing the cause of the break, Cesario said. Mueller said the rain was likely a factor. The conditions in the clay-like soil in Sharon Heights changed with the weather, Mueller said. The main break in October happened under dry soil conditions, but when it started to rain, different pressures from the wet soil were exerted on the pipes as the water was absorbed, causing the break, he said.

Olivera said he will provide more information on Thursday's main break when the department completes repairs.

On Oct. 25, a pipe burst at nearby 720 Monte Rosa Drive, flooding numerous classrooms and prompting officials to close the school for two days.

Parent Jud Hoffman emailed council members on Thursday night to make sure they were aware of the main breaks, he told The Almanac.

Both Hoffman and his wife work, so the school cancellations were "understandably, really inconvenient," said Hoffman, who has twins in the sixth grade. He said the district has done a good job keeping parents updated on the floods.

The district was still in the process of assessing damage from the October incident when the campus flooded Thursday.

In the October incident, water leaked into nine of the 21 classrooms in the Menlo Park school’s new two-story building, which opened this fall. The water main break impacted 17 classrooms at the school, which has about 800 students enrolled.

None of the four classrooms impacted Thursday is in the new building, according to Cesario.

A $60 million facilities bond measure, which passed in November 2013, helped fund the new building. Funds also went to the district's elementary school, Las Lomitas Elementary.

Almanac staff writer Kate Bradshaw contributed to this report.

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