Thanks Danemayer, I understand that the 3 main tanks are heated. However, I do have a full bath in the rear garage area with separate tank pull valves. A black and grey up front, and a black and grey in the rear. I assume the front grey is for the shower,kitchen sink, and washing machine drains. I assume the rear is for the rear sink and shower. The front black tank for the front toilet, and the rear for the rear toilet. But, the rear tanks are not covered by the underbelly with them being in the garage. I did not notice any type of wrap around the rear tanks, so I was wanting to make sure before I try to use the rear bathroom this winter. Thanks for your help.