Just realize though that, unless you store your water heater full, you have to use 6 gallons of fresh water to fill it before water will come out of the tap. Or, you could always just put containers under the fresh water tank drain port under the camper to access water, which is was my plan, since I don’t keep the water heater full to minimize corrosion.
And when I do sanitize, I use non-scented chlorine bleach. I can’t remember the concentration, but it isn’t much. Something on the order of 1/4 cup per the 20 gallon tank, then let it sit, and then drain and rinse.
But, that doesn’t get the water heater, or the lines. I’m just assuming nothing ever grows there.
Dave