Heat on vs winterizing

You don't need any antifreeze in the fresh tank. Drain it good and what ever very small amount is left wont hurt anything. I usually open the drain and let it drain, and then tow it to the storage facility to get those last drops out. Then close the drain. My wife had a dog grooming business and a couple of times I forgot to drain the tank and it froze solid. Didn't hurt it. I'm not recommending that you leave water in it but, residual water freezing in the tank won't hurt it. In the grooming van I could only drain it down to about an inch and that inch froze hard as a rock many times and never threatened to hurt anything. Nevertheless, antifreeze in the fresh tank does more harm than good in my opinion. Really, if you feel you need to use it the places that tend to break from freezing is the faucets. My brother has to replace his sink faucet every year because he won't winterize. He turns on a small space heater in his camper on really cold nights but, that doesn't save the faucet. If there were no water in there, like blowing it out with air, it wouldn't break.