Fresh water tank full when traveling?

do this a lot full tank half tank quarter tank my tank is in middle of coach have never felt a difference

We never, ever leave home or any other place where water is available without a full tank of water. The weight of the water is not an issue for us, as we have enough CCC to handle it. Any potential impact upon fuel mileage is not something we care about.

I do think you have a point about the sloshing effect. 200 or 300 pounds or more of water moving from side to side can't be good.

I can't speak to the sloshing effect, but I always fill my tank prior to traveling. I'm just one of those who likes to be prepared, and who knows when even a new MH will break down in the middle of nowhere. As far as expense goes, water weighs something like 8.24 or 8.34 lbs per gallon (not home and don't have the exact number at work), so you can always do the math to see the possible budget impact.