The method varies with the coach. Sometimes the only way to drain is to pump the water out. On my coach, the tank is drained by opening the low-point drains on hot and cold and then turning the pump on to push the water into the water lines and out the low point drains.
Former owner of 2004 American Tradition and several other RVs
Home is in the Ocala Nat'l Forest near Ocala, FL
Summers in Black Mountain, NC