I had one RV that required the water pump be running to drain the fresh water tank. I just drained it to 1/4 to insure that the pump didn’t run on empty. Gravity got the remaining water out.
2015 Fleetwood Excursion 33D
2016 Grand Cherokee Limited
Retired Law Enforcement
U.S. Army 1965-1973/RVN 1968-'69
I am the frequent recipient of "Get out of the way old man!"