HI, we have a 2011 Big Country, and we have the same problem. We are from South Dakota and are still here until tomorrow when we head to Arizona. Last year we bought our new rv in Texas and because of the unseasonably cold winter we had there we expierienced freezing problems also. I found out the problem lies with the pipe that lies next to the frame that brings water from the tank up to the water pump. The water pump area stays plenty warm but the line going to it freezes up. I am very upset with this and Heartland has known about this problem for years, just go back and read the old posts. The only way, we as owners have to solve this is to take the bottum of the rv off and box this line in or insulate it, or we pulled the floor register in the living room up and installed a [T] under it that would direct more heat into the under belly area. We bought a floor vent that we can close so it forces air down under. We have never froze up since. I installed a remote thermometer under the kitchen sink area with the probe down by the water tank, you won't believe how cold it gets there. Even in Texas with the frnance running we were registering temps like 33 regularly. Taking off the bottum looks to be a big task and I wish I had the time to do it, because I know if this line freezes up here in the North country it might never thaw until spring. In making the rv it would take the Heartland a few seconds to insulate this line and we wouldn't have this problem. We have had 5 5th wheels now and this one is the only one we ever had freezing problems with. Hopefully we won't have to fight this problem this winter in Arizona.