City residents are being urged to boil their water after a main broke Wednesday afternoon. A large rock near the U.S. 19 entrance of Werner-Boyce Salt Springs State Park settled into the ground about 1:30 p.m., drilling a 6-inch crack into the northbound water pipe, utilities director Pat Stewart said. Officials posted a notice to residents between Ridge Road and State Road 52 that they could see low or no pressure for up to 72 hours. Stewart estimated between 800 and 1,000 homes and businesses could be affected. Crews began working to cut the cracked pipe and resection it, Stewart said. He estimated the work would likely finish by Wednesday evening.