Two floors of the Wareham Middle School filled with smoke Wednesday afternoon after a water heater burned up, according to Wareham Fire Chief Robert McDuffy.

Wareham Fire Department received an alarm call at 11:01 a.m. from the Wareham Middle School. McDuffy said that, when firefighters arrived on the scene and realized two floors were filled with smoke, they called for backup.

Students are on vacation, but some staff members who were in the building needed to evacuate due to the smoke.

All told, there were three engines and one ladder company on the scene from Wareham and Onset fire departments as well as Wareham EMS.

McDuffy said that, after a preliminary search, the hot water heater on the first floor was found to be the cause of the smoke.

Firefighters began leaving the scene at 12:05 p.m. as a plumbing inspector checked the water heater.

McDuffy stressed the importance of having a functioning fire alarm system.

"We would have had a serious fire on our hands if we didn't get an early warning," he said.