Preschoolers and kindergartners at Star of the Sea Early Learning Center in Kahala get to go to class in the big kids' school this week, but it isn't a field trip.

The school at 4470 Ali'ikoa St. was flooded on Friday when storm runoff and sewage backed up through bathroom drains, creating lakes among the books and building blocks.

City officials say the flooding was due to heavy rains and backup from the same sewer system that flooded Kahala Mall.

The children are taking it in stride.

"I went to the library," Daniel Balabis, 4, said as he caught up with his father, Allen Balabis, at the Early Learning Center. Daniel was one of about 190 students set up in temporary rooms, including the library and music room, at Star of the Sea Elementary while workers ripped carpeting out of the Early Learning Center. About 40 other students, all toddlers, were not affected.

Three large classrooms were flooded. Desks and chairs were stacked up along walkways as cleanup continued yesterday. Outside one room was a piece of timely student artwork: a boat made of sticks against a watery background. The student had labeled the work,"Noah's Ark."

"They like going up to the elementary school," Allen Balabis said. "It's a big adventure for them because they took their naps somewhere new — like a sleepover."

"The kids are happy no matter what," said Lisa Foster, school principal. "They think, 'Oh, we get to go to the big kid school.'

"Next on my agenda? Get sandbags."

Foster hopes to have the classrooms back into shape by Monday, but said she thinks April 14 might be a more realistic date.

Foster said water, mud and sewage started seeping in from drains in the bathrooms, each of which is inside a classroom, about 1 p.m. Friday. The watery goo spread from the bathrooms to the classrooms and out onto the walkways.

Teachers and staff members came in on Sunday to help try to salvage classroom equipment. The school is replacing carpets because of health concerns, Foster said.

Mark Matsunaga, a city spokesman, said the flood was the result of the same overloaded sewage system that temporarily closed Kahala Mall.

He encouraged O'ahu residents to make sure their rain gutters don't empty into the sewer system, and to avoid removing manhole covers in attempts to drain runoff during floods.

Foster said she brought in a contractor to test for mold and mildew and was relieved that the school, which has operated more than a quarter-century but moved into its new building only two years ago, seemed to have avoided those plagues.

Air quality tests are still pending, she said.

Reach Karen Blakeman at kblakeman@honoluluadvertiser.com.