Winter caravanning

My wife and I enjoy caravanning all year round.  In our previous caravan, the water container was a plain white jerrycan inside the front locker, where it was protected from freezing.  We have just bought a new 'van with the standard external water container connection with which we use an Aquaroll.  I am concerned that the water in the pipe will freeze and in a severe frost the water in the Aquaroll will freeze.  Are there any tips out there, please?  How do other winter caravanners manage?