I am new to living quarters on a horse trailer. This is my first one. It is a simple living quarter with a 30-gallon freshwater tank. It has no water heater/shower/toilet. It does have a sink. The water just drains out of a pipe from underneath the trailer. What do I need to do for winterizing it? I do live in MN so I am sure I will need to do something, but I don’t have the typical LQ trailer so I am just not sure what I need to do. TIA for the help!
We have simple LQ w/o toilet but with a water heater, shower, and sink.
First I drain the 50 gal. trailer tank through a low point drain and open all the taps in the trailer and “cowboy shower” in the horse box. Turn off the taps. Close the tank drain.
Then I put 6-8 gal. of antifreeze into a big, aluminum pot. Using a small submersible pump I bought from Northern Tool I put the input foot into the pot and the output to the regular hose connection on the side of the trailer. Then I set the trailer water valve to the “city water” setting an turn on the pump. Now antifreeze goes into the entire system except the 50 gal. tank. I run all the taps until each produces antifreeze. Note that the hot water heater hold just short of 2 gal. so I have to purge the untreated fresh water from the heater by just running the hot water tap in the sink until I get antifreeze. Cold water is not a problem. I do the same to the shower lines and fixtures in the horse box. Then I move the valve to the “fill tank” position and fill the tank with whatever I have left. Last, I turn on the tank drain until it runs antifreeze. Last I turn on the 12v. trailer pump and run it for a few seconds while it draws from the tank.
Now ALL the water lines in the trailer are protected.
This sounds more complicated than it is. It takes a bit of time but a whole lot less time than it will take to fix a broken trailer water line. 
G.
Could load up and move to Florida for the winter
To drain the lines you might do better to use compressed air to blow the airs clear (remember to turn the pressure output of the compressor down or you may blow fittings)
This is a great video about winterizing. I just load it on my iPad every year, and go step by step through the trailer with it.
