Always intresting to see what different people do to winterize their water lines. We have been doing the RV (one kind or other) thing for about 50 years and wintered in most states. I now blow the lines on our motorhome, bypass and drain the water heater for light or short term freezes. I use antifreeze if its getting real cool (zero F or lower) and bypass and drain the water heater. So I love the bypass valve on our rigs. The only lines I have froze in our travels are the P traps on the sinks. No matter what you do, you need to protect them. RV antifreeze works but so does windshield washer fluid. We use -50. Its limited fun to clean up the mess after you find a P trap frozen and broke.
