When we had trailers we carried a few gallons just for the toilet if need when traveling , if it was a trip from home to a campground or campground to campground with hookups or a park with a community water supply we would have empty tanks when traveling it was more of a weight issue and not wanting water sitting in the tank not being used. We do the Same thing now with a TC but definitely more for weight now ,but If boondocking or dry camping we will carry a half tank . Your trailer should be able to carry a full tank of water and some tanks are more like a bladder they are plastic but expand when full , At least the ones I have had over the years
Mike
