Some residents in Stamford are still cleaning up after a water main break caused some major problems Thursday afternoon.  The water main burst near a fire hydrant in Belltown around 3 p.m., sending loads of water down Oaklawn and Halpin Avenues.  The water poured into at least two homes on Halpin Avenue, flooding the basement of one residence with over five feet of water.  The cause of the water main break was unknown, though investigators believe the break was unrelated to nearby sidewalk construction on Oaklawn Avenue.