Put the jacks down on drivers side and create an angle that drains to the side valve. Just don't take all the weight off the suspension but if you are level or angled slightly to that side before you start you'll get quite a bit of it out. Then you can also you hook up the hose and start filling and leave the drain open for awhile to further dilute and drain out remaining "leftover" water you are trying to get rid of.
2008 Berkshire 360QS-40
"If you can't fix it with a hammer, you have an electrical problem"
I do that tilt with the jacks to drain the tank too but maybe the OP was asking how to be able to use that last 1/3 of water. As our coach is already overweight I try to travel with as little water as possible but cant access much below the 1/3 full mark so I end up traveling with just a few gallons above that just to be able to use bathrooms while on the road. Hauling all those extra gallons up to the 1/3 indicator is frustrating as our coach has to bring along a couple hundred pounds of useless weight. Ok feel free to add in your own DW or DH joke also in that regard!
mjracsj, yes that is what I trying to convey. At one time someone posted how to adjust a tube that the water is pumped from to go lower in the tank. Would just like to know which tube it is and how to do it. Thanks