Water weighs in at 8lb to the gal and we do not fill the water tank. I put in about 1/2 tank based on the water level meter comes out to about 15 gals. So the weight penalty is not that much plus we only use it for dish and hand washing and the toilet so really not a whole lot needs to be transported particularly if you stay in campgrounds where you can add as needed. We use the facilities in the campgrounds and have never used the bath/shower in any of the units we have had. Put a large ice chest in the tub/shower instead since the refrig is small in most cases. carry about 2 35 unit case of water and a couple of gallon jugs. have never needed more in our travels.