SWAMPSCOTT – Residents of Shelton Road were without water most of the morning on Friday.Department of Public Works Director Gino Cresta said a small water main in the vicinity of 89 Shelton Road broke just before 7 a.m. on Friday and it took crews almost seven hours to repair the main.”The water was off for approximately four hours,” he said. “A 6-inch main broke and we had to replace approximately two feet of it,” Cresta said.Cresta attributed the break to the age of the water main and the extremely cold temperatures.”We had a couple of breaks in the same vicinity last winter,” he said. “We hope to replace the entire main sometime in the next couple of years assuming the MWRA (Massachusetts Water Resources Authority) extends its program of no interest loans.”Last February, 6-inch mains near 51 and 62 Shelton Road broke within hours of each other.Cresta said the town has funds from the MWRA Local Pipeline Assistance Program at its disposal to reline the water main on Humphrey Street from Salem Street to the Marblehead line.”We’re hoping to start that project this summer,” he said.Cresta said the town is in its last year of a $5 million, 10-year water main replacement program that, when complete, would replace a good portion of the aging water mains in town.”We will have relined or replaced 15 percent of the mains in town,” he said. “We started with the main transmission lines coming into town but we have a lot more to do.”Cresta said he expects it would cost upwards of $45 million to replace or reline all the aging water mains in town.