THE BRONX - Hundreds of residents on Union Avenue were left without water Friday as environment officials investigate a possible water main break.Neighbors say they woke up to a flooded street and were then told by the Department of Environmental Protection that their water would be turned off.Officials drilled through the street to determine the exact cause of the problem.Residents say their main concern is for the Davidson Senior Center where 200 senior citizens are living without water. The super of the building wants the city to step in and help.?It?s very painful. I hope the city sees this and supplies some help for these people,? says Connie Perez.People are also concerned about when regular traffic will be restored to the street.