Five New Gloucester residents were roused at 4:30 a.m. by a family dog to a fire burning at the back of the house.

Firefighters responded to 12 Abby Lane off Route 26 and found fire at the rear of a house, which consisted of a main house, an ell and a barn.

The dog’s owner, on the second floor, and a family of four tenants on the first, reported that when they awoke, the house was filling with smoke, but they all got out safely, said Capt. Scott Doyle, who was the first firefighter to arrive. He called in a second alarm, summoning help from Gray, Raymond, Poland, Pownal and North Yarmouth.

Before any fire equipment arrived, the driver of a passing Poland Spring Water tanker truck saw the fire and stopped and soon was emptying the truck’s load of 8,500 gallons of water into a 10- by 10-foot portable impoundment fire companies use to shuttle water from tankers to hose companies.

The fire was knocked down in about an hour, and fire damage was confined to the rear of the building, though smoke damaged the interior throughout the home. Damage was estimated at $150,000.

Investigators are trying to determine the cause and whether smoke detectors worked on the second floor and whether any were installed on the first floor, he said.

Doyle urged residents to make sure they have working smoke detectors and to change the batteries twice a year, when changing the clocks, which passed last weekend.

David Hench can be contacted at 791-6327 or at:

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Twitter: @Mainehenchman