EVERETT — Three water mains in the city of Everett have broken since Monday, causing 28 homes to lose water service.

At 8:15 a.m. Tuesday, a 6-inch cast iron main broke near 10th Street and Colby Avenue in the Northwest neighborhood. Water service was interrupted for 15 homes until the repairs were completed at 11:05 a.m.

On Monday afternoon, another 6-inch main broke in the 900 block of Maple Street in the Delta neighborhood. Service was cut off for 13 homes while repairs were under way.

In both cases, the mains dated from the post-World War II period, when construction quality was substandard.

It is not known if cold weather contributed to the pipe failure, only that breaks tend to occur when temperatures fluctuate above and below freezing, said Kathleen Baxter, a spokeswoman for the city’s Public Works department.

Soil movement could trigger a main break, she said.

There were at least six breaks in last week’s cold snap, and most of those were in pipes dating from 1945-1955.

Everett has 33 miles of cast iron water mains from that era in its 415-mile system. Most of the post-war pipes are in the north end of town.

The city has committed to replacing them with modern ductile iron pipes.

“We’re just going to double down and get rid of our cast iron,” Everett’s Public Works Director Dave Davis told the City Council on Jan. 11.

Also Monday afternoon, a main dating from 1967 broke in the Silver Lake neighborhood. It was repaired quickly and no homes lost water service.

People who temporarily lose water service should run the taps until the cloudiness clears before using it, although the water is still safe to drink.

Chris Winters: 425-374-4165; cwinters@heraldnet.com. Twitter: @Chris_At_Herald.