MY HUSBAND AND I JUST BOUGHT AN OLD HOUSE WITH A CISTERN IN THE BASEMENT,SURROUNDED BY CEMENT WALLS AT ONE END.IT DOESN\\\'T LOOK LIKE IT\\\'S BEEN USED FOR YEARS, BECAUSE THE GUTTER OUTSIDE THE HOUSE WAS RE-ROUTED AWAY FROM THE DRAIN PIPE THAT BRINGS THE WATER INTO THE CISTERN. WHAT SHOULD WE DO WITH THE WATER THAT IS STILL IN THE CISTERN? WE FIGURED THAT STANDING WATER PROBABLY ISN\\\'T SO GOOD TO HAVE IN THE HOUSE. WE DON'T KNOW HOW LONG THAT WATER HAS BEEN IN THERE. HOW SHOULD WE GO ABOUT DRAINING IT, TO MAKE SURE THAT EVERY LAST DROP IS REMOVED.