Hundreds of homes in Cumberland Center were put under a boil-water order Wednesday and schools were shut down after a large water main broke on Winn Road.

The boil-water order, effective until further notice, affected about 600 homes in Cumberland Center, said Michelle Clements, spokeswoman for the Portland Water District.

The order recommends that consumers boil water used for drinking, washing food, making ice cubes or brushing teeth for one minute. “It’s only a precaution,” Clements said. “We have no evidence that the town’s drinking water has been contaminated.”

The water main break, which was reported around 1:15 p.m., forced schools to send students home early Wednesday. Superintendent Jeff Porter announced later in the day that all schools in School Administrative District 51 will be closed Thursday.

Porter said his decision to close Greely High School, Greely Middle School and the Mabel I. Wilson Elementary School means that more than 2,000 students from Cumberland and North Yarmouth will not return to classes until Monday, with Friday off for the Veterans Day holiday.

Porter said he was told by the Portland Water District that it will take 18 to 24 hours for the district to test the water to make sure it is safe to consume. That warning convinced him to send a notice to parents and guardians late Wednesday afternoon announcing that all classes and recreation activities held in the schools were canceled for Thursday.

“In consultation with the Portland Water District and the Cumberland Fire Department, it was determined that the safety of the water in the schools cannot be guaranteed over the next 24 hours. Water testing will not be completed until Thursday evening at the earliest,” Porter told parents.

Clements said crews were on the scene of the water main break for most of Wednesday, trying to repair the damage. Winn Road remained closed Wednesday night between Range and Main streets.