Turn your waterbed heater off and disconnect it from its power source.
Remove the cap and plug from your mattress and pull the fill valve out of the mattress.
Insert the hose connector from the waterbed fill kit into the fill valve.
Surround the valve with books or other heavy objects to keep the hose connector in the water.
Attach the short hose, which is attached to the suction side of the pump, to the hose connector.
Connect the garden hose to the outlet side of the pump and run the other end of the hose to a bathtub or out a window so the water has some place to drain.
Turn the waterbed pump on.
Lift the mattress from the head of the bed to allow the water from the head and the baffles to flow to the foot of the bed.
Roll the mattress from the head of the bed toward the foot to keep squeezing water out of the mattress as it drains.
Turn the pump off and remove the fill valve from the mattress.
Pull the mattress away from the sides of the bed.
Roll or fold the mattress in half to make it easier to carry, making sure that while you're doing so you are holding the baffles in place so they cannot move around.
Lift the empty mattress out of the bed and move it to its destination. If you're storing or transporting the mattress, make sure that it is laid flat so the baffles cannot move around.