Plus 1 on the water hose freezing at night.
In Feb 2014, we had stopped at a Ameristar Casino CG Vicksburg, MS. The lady who checked us in, said we probably shouldn't hook up the water hose as it was going to freeze that night. Freeze isn't the half of it. Vicksburg set a record low of 17 that night. Fortunately, no water lines froze in the TT.
Later, while in San Antonio, TX, I did have my hose hooked up, and it froze overnight. Disconnected that morning and it thawed out during the day.
K3WE wrote:
How about this for an answer: IT DEPENDS! and maybe 'enjoy the choice'.
If you aren't staying particularly long, hooking up the hose is one less thing to do. Also, if things get a little cold at night, your hose can freeze while your tank probably will not. On a recent trip- we were worried about a water leak. Filling the water tank and working the on-off switch was a pretty convenient way to address the situation. Dittos that sometimes campground water might have a 'local flavor'...again, the choice to 'carry your own' is just that- a nice choice.