Draining Your Skoolie Pipes for Winter Using an Air Compressor

Ted Tibbetts // December 4 // 0 Comments

Ever have your pipes freeze?  

Not fun.

I think the first time I ever heard my dad swear it was when the pipes froze and burst.  (He’s not usually a profane man!)

When I was a kid we lived in an old drafty farmhouse in Maine.  Dirt and granite foundation. One “polar vortex” week in winter the pipes froze.  I was helping my dad thaw them out with a hair dryer in the dirt basement.  When we finally got the ice melted, water started spurting from all the cracked pipes and we had to rush to turn the water off, then repair all those broken pipes.

I don’t want to relive that in the bus, so, with polar vortexes approaching, it’s time to drain the pipes and put Snug to bed for the winter.

Of course, I should have done this when I actually did the plumbing.  Why didn't I?  I have no idea....

Why use compressed air?

As much as I would have liked to, I wasn’t able to design my plumbing system so that all the supply lines drained to one low point.  Thus, there are low spots that I know have gathered water, and I want it out of there so that it doesn’t freeze, expand, and crack the fittings.

The best way that I can think of is to tie my compressor into the system and force the water out!

Tools Required 

Oil-less air compressor

Air hose with fittings

Pex Cutter

Plumber’s thread compound or teflon tape


Pex ring crimper  if you want to use crimp connections...use shark bite fittings if you don’t have a crimper.  (This is the one closest to what I use...but do your research and see which one will work the best for you!)

Materials Required  

If you have ½” supply line:

¼ “ air hose fitting

½-¼” bushing  (This is a pack of 2, but you only need 1...if you can find only 1!)

½ to ½ female Shark bite adapter  (Or ½-½” crimp ring connector)

½ Push to connect ball valve

(I already had a ball valve, but it was threaded, so I needed these adapters…)

2 @ ½” to ½ Male adapters (Shark bite or crimp ring)

½ Ball valve

½” T  (Shark bite or crimp ring)

1’ ½ Pex pipe

If you have 3/4” supply line:

¼ “ air hose fitting

½-¼” bushing

½ to ½ female Shark bite adapter  (Or ½-½” crimp ring connector)

2 ½” to ½ Male adapters (Shark bite or crimp ring)

½ Ball valve

¾-¾-½” T

1’ ½ Pex pipe

Building the Air Chuck Port

using thread compound
  • Coat all the threads with thread compound or teflon tape.
  • Screw the air hose fitting into the bushing
  • Screw the bushing into the ½” pex adapter
  • Insert a section of ½” pex into the adapter (I like putting in a longer piece then cutting it down to a couple of inches...it gives me more to grab!)
  • Trim the pex down to 2 inches
  • Screw the ½ male pex adapters into each end of the ball valve
  • Insert one end of the ball valve into the pex attached to the air fitting
  • Insert the other end into another section of pex, then trim it down to 2”
  • Insert the open end of the pex into the outside port of the T
compressed air port for purging water from plumbing system

Tying the Valve into the System

  • Drain as much water from the system as possible
  • Have  bucket handy to catch any remaining water
  • Use the pex cutters to cut the supply line.  (I cut mine as close to the pump as possible to maximize the amount of pipe I could purge.
  • Push one end of the T onto the pipe you just cut.  (Twisting back and forth as you push seems to help!)
  • With a sharpie marker, mark the other side of the pipe where it will end at the end of the “bulge” in the T-fitting
  • Cut the T fitting
  • Push that end of the pipe into the T-Fitting
push connect air port into plumbing system

Blowing out the Water

Most articles I read recommend setting your air compressor output to 40 PSI.  This will provide enough force to push out the water, but not so much that you damage any parts of the system!

setting correct air pressure to purge pipes

Also, it’s a good idea to use an oil less air compressor.  An oil-lubricated compressor will force oil molecules through your fresh water pipes...and you don’t really want oil in your drinking water!

So, adjust the settings on the compressor and, with the ball valve closed, hook the air hose from the compressor to the air fitting.

Consider where this expelled water is going to go!  If it will just blow into the sink or shower, then go down the drains, then you’re good to go.  Rather than trying to force water up to my sink faucet, I disconnected the supply lines under the sink, and put a bucket under them so that water could drain down into the bucket.

purging water from skoolie pipes

Similarly, I put a bucket under the drain of my hot water heater.

Turn the compressor on, and when the pressure has built up to the appropriate level, slowly open the ball valve.  

Check all your open valves.  You should be able to feel air coming out.  When there’s only air and no water, you’re done!

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About the Author Ted Tibbetts

Ted, a teacher, raft guide and carpenter, has been teaching high school English for over 20 years. A Milken Award winner and a Maine Teacher of the Year State Finalist, Ted loves working on his Skoolie, "Snug," and traveling around to splash in rivers.

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