Draining/winterizing plumbing

Since a lot of you have seasonal places, I figured this would be a good place to ask about winterizing plumbing. I built a full bathroom in my barn, which is very handy, but it does get below freezing in there during the winter. It was 29 in the barn the other day. Once we live here full-time, I'll probably just drain the pipes for the first cold snap, and leave the water off until spring.

Now for the questions-

Should I try to drain the PEX pipes? When I shut the water off and open the faucets, most of the water remains trapped in the piping. I know PEX can tolerate some freezing, but wouldn't it be better to purge the water out? I thought about making an adapter to go on the work sink faucet so I could use (low) pressure air to force the water out.

What about the toilet? I can drain the tank easily, but what about the trap? We used to have a summer cottage, and used a sponge to get the water out of the trap for winter, but then what about sewer gas? Would you leave the water in the trap, or drain it and plug it somehow? The same goes for the two sink traps.

I also have a small water heater. I guess it would be prudent to drain that as well?

Right now, I have a shut-off at the street, and a shut-off inside the barn. I'm going to add an underground shut-off outside the barn, and fit it with a drain as well, so I can drain the supply going into the barn.

I could keep a small heat source near the critical areas, but an ice storm could leave us without power for a week. I'd rather just winterize. Thoughts?

Ideally you need a drain point at the lowest portion of your lines. I shut off the supply from the well. Open all lines both hot and cold to drain to that lowest point including the hot water tank. Shut off supply lines for the toilets. Pour RV antifreeze in the tanks with the water and flush. Then I purge all the faucets with air making sure I start at the highest elevation first moving the hot/cold selection to get both lines to clear the faucet (cartridge style) of water. Make sure you drain the pressure tank as well. I normally leave all my lines open afterwards so they continue to drain and there is no pressure so that if there is a portion left that wants to freeze it will expand to an open line and not bulge.

I attached a air tool fitting to a female water hose connection, screw it to an outside faucet , turn down the air pressure on my air compressor and blow everything out backwards until the inside faucets are just blowing air, slop some RV antifreeze into the the p-traps, drain the water heater and done. I use the same technique to clear out the underground water lines to the well.

With the different sizes of faucet and some having internal and external threads I found it very easy to just pick up a tire valve. I use a portable air tank and just hold the valve up into the faucet and hit it with the air tank. Just a little hint. I leave the screen fitting off the faucet until warmer weather. Once I turn the water back on and get it back to normal I reattach the faucet fitting. That purges all the sediment out and will not clog up the screen.

I would plumb to blow out and drain. I would drain the water heater for sure. The toilet and / or / of a lav sink traps just pour RV anti freeze into them. They make a valve known as a stop and waste. It is buried in your main line usually outside with a long handle on it. When turned off it will allow the water to drain down like a frost free hydrant however I would still blow and drain as much as possible.

The house we are planing on building will include most the methods for winterizing you mentioned and we plan it being our full time residence. However I would not rule out snowbirding to the south in the winter time as we grow older. We are holed up in Yuma in the fifthwheel currently without a home. So we are very mindful of the importance of being able to drain and leave.

Your concern over power outages is very well founded if you live where it gets cold. A railroad buddy of mine has a very, very nice cabin up at Henry's Lake, Idaho near Yellowstone (very cold country) A tree fell on his property and took down the power lines no one knew it. In turn this froze his cabin big time. Doing so of course destroyed a lot of plumbing and flooring and such. He now preaches winterize even if you live there full time and you are going to be gone a day or two.