Winterizing - Extreme cold winters

swimmer_spe wrote:
So, I am ready to winterize my trailer's water system. I have a nice full brass fitting, an air compressor that can be adjusted for 30psi, and an air line.

Now, I know some of you know how to do this, but do you know how to do it for 'extreme' cold winters? We regularly get -30C(-20F) and colder.

For those who have those extreme temperatures over the winter, do you use antifreeze? How?

Here in Minnesota (-30!): I blow out all the lines with the compressor. Then I set the water heater valves to the by-pass position, and leave the big drain plug out for the winter. My water pump has a winterizing inlet tube and a couple of valves to change so the pump sucks from the tube rather than from the water tank. Stick the tube into a jug of antifreeze, turn on the pump, and then run all the taps, showers (in and out), low point drains, etc. until antifreeze comes out. Usually takes about a gallon and 1/2. The rest I pour into toilet and traps.
While just blowing out all the lines is probably pretty sufficient, I think this is one area where a belt and suspenders approach is warranted.

BTW - most bursting of pipes is due to air trapped between areas freezing water (or water and closed valves), not the ice itself. As the ice expands, the trapped air rises in pressure, to the point where the pipe or fittings give way.