A call was received from the MCR at approximately 21:30 on Monday June 27th to report that active drains in the east end of the Meson Hall were backing up and overflowing.  I came in and found the leak coming from a broken spray nozzle in a sink in the rad waste area.  The leak was stopped at which point there were puddles between 1-2m diameter around the active sump top flange, the drain directly south of the warm cell water windows, and the drain in the counting room south of the clean room.  There was lots of water on the floor in the rad waste area as well.  No water was found in the TR-13 area.  A swipe was taken from the puddle around the active sump top flange, which was not above background level.  Robin Swanson (ops) contacted Joe Mildenberger who gave permission for the sump to be pumped out after a water sample was taken.  Robin took a water sample and left it for analysis by RPG, the sump pump was started and ran overnight.  At approximately 8am the next morning the sump was almost empty and the pump was stopped.  Floor swipes were taken where there had been puddles which were now dry - no contamination found.  The areas in the hot cell lab which had been wet were mopped.