The reason we drain ours is that it is keep at a campground site until used it to travel and the water there is from a well. Well water does not have the bacteria killing chemicals that city water has for long term storage, plus left in that hot aluminum tank for some times weeks on end. I had installed a brass ball cock valve into the nylon plug from instructions on one of the poster idea here, years ago, and it just a matter of turning that valve to drain or close to fill. Making it no big deal at all.