What does it mean when water is dripping from the ac unit in the house How do you stop your central AC from dripping water in the return air vent?

Water will condense in the inside unit of the air conditioner. This is because the coils in the unit get cold (ad expected) and moisture in the air condenses on them like moisture on a cold glass. There should be a drain inside the unit to drain this water. Check that it isn't clogged.