We always travel with "some" fresh water in the tank, road-side stops being the main reason. But we were camped last July, at a private CG in the Hocking Hills region of Ohio, when a "dereche" windstorm blew through, bringing down trees and limbs throughout the entire area. Power was out and roads were blocked for over a day. Like the OP, we were not without water nor power, thanks to our two 12-volt batteries and 1/2 tank of fresh water. Everyone else was left carrying 5-gallon buckets of water to flush, even for the toilets in the CG bathrooms.
I can't imagine the angle-iron braces bolted and welded to the frame, under the water tank, not being capable of supporting the weight of 20 gallons +/- of water, and yeah, I know that's 160-200# of added weight. The peace of mind in having this resource available far out-weighs the risks that are condemned by the "weight police".
