Holding Tanks in cold climes

[TsnTexas]

As we are new to travel trailer camping I'm wondering if the holding tanks will crack when the liquid freezes inside them. We often camp in "off the grid" nat'l forest campgrounds where the nighttime temps get down into the low 20's. I don't think it's practical to run heat strips off the battery. I suppose you could add an antifreeze product to the black and grey water, but obviously not in the fresh water tank. Question is - what are the guidelines for camping in freezing conditions? (by the way we're in the process of buying a Rockwood 2504s)
Thanks for your input in advance!

[VizJedi]

I know the manuals all say to drain the black, grey and fresh water tanks when winterizing. In the 14 years I have owned trailers, I have probably had some liquid in the holding tanks more than I haven't. And never had a problem.

As long as the tank isn't completely full, the fluid freezing will have room to expand and not cause any problems. There could potentially be problems with drain pipes and valves, but I never had any issues with 4 different trailers.

Now, water lines are another story. Small, contained tube with no room for expansion = broken water line.

j

[Dwilcox]

If you have some water in the bottom of the tanks there should not be a problem, if you have water trapped between the drain valve and the cap, well that could be a problem.