ROCHESTER — The city is in the process of repairing the 1 million gallon water tower that forced an evacuation along Route 108 in December.

The tower, which was built in 1985, has been empty since the city drained it when a significant leak occurred Dec. 12, 2011. An engineering study must be conducted to ensure the tank, its base and all the components are structurally sound, according to Robert Gray, chief operator at the Rochester Water Plant.

“We’re in the design phase,” Gray said, adding he hopes the tower, which will cost an estimated $500,000 to fix, should be back online by the winter.

Gray said the cost of the project will be finalized once the engineering study determines the extent of the repairs. He added the city continues to investigate what ruptured the pipe at the base of the tower, which caused water to gush down Rochester Hill and led to the evacuation of about a dozen homes in the area as a precaution. Gray said the tower, which when functioning provides water to the area around Rochester Hill and along Salmon Falls Road, served a large portion of the city. Nonetheless, he added there is no impact to the city’s 10,000 customers as there is a million-gallon tank on Chesley Hill Road and a two million gallon tank on Salmon Falls Road. Using water stored at the city’s facility along Pickering Road, it will take about a day and a half to refill the tank, which will cause no significant impact to water pressure or service to the city, Gray said. Concerns should contact the Water Department at 335-4291.

jquinn@newstote.com