2001 Honda Civic WATER LEAKS INTO PASSENGER FLOOR BOARD

QUESTION?...WHY DOES WATER LEAK INTO THE PASSENGER FLOOR BOARD, FROM UNDER THE DASH, WHEN MY AIR-CONDITIONER IS ON AND HOW DO I FIX/REPAIR THE CAUSE?...IS THERE A HOSE/DRAIN STOPPED UP?...AIR-CONDITIONER SEEMS TO COOL FINE...THANKS FOR THE HELP IN ADVANCE!!!