I found this message attached to a pipe in the first house I bought

Tag hanging from a pipe


Winter Drain Instructions:

  1. Close valve in October before winter freeze
  2. Open air bleeder valve on side of main valve
  3. Open exterior hose bib
  4. Pull down pin in centre of back flow preventer until all the water has drained

I'm not sure what the winter drain is.

What will happen if the valve is closed?

What is the air bleeder?

What are the rest points?

What do these points mean and what for?

  • 1
    Find the route this pipe takes to an outside hose bib. Add pictures here of any valves, caps, or other controls you see near the sign or along the way, and of the faucet outside. Label, if you can, the valves, caps, and controls as A, B, etc for easy reference using a photo editor. Then we can help you relate these instructions to the things you need to do.
    – jay613
    Jul 24, 2022 at 21:37
  • 4
    upvote for sweet photo of actual note
    – Willk
    Jul 24, 2022 at 21:54
  • 12
    "Winter drain" where drain is a verb, not a noun.
    – Ecnerwal
    Jul 25, 2022 at 12:54
  • 4
    They seem to have forgotten: "1.5) remove the hose" which in my experience is the main mistake people do the first winter they own a house
    – Jeffrey
    Jul 25, 2022 at 14:57
  • You find similar things in vacation homes in cold regions where the entire water system needs to be drained for cold weather if the heat is to be off. For that, you might want to talk to a plumber to be sure you understand.
    – Buffy
    Jul 25, 2022 at 19:30

2 Answers 2


An air bleed valve looks like this

Sharkbite bleed valve

You'll note

  1. The directional arrow
  2. The cutoff valve (red handle)
  3. The air bleed valve (the knob past the cutoff)

The reason for this process is that once you shut off the water, there's nothing that will relieve the pressure. You can open the other end and nothing will come out because there's nothing to replace the water with. By turning that valve, you allow air to enter the line. You need to then open the other end of the setup (a hose bib in this case).

The other step is you have a backflow preventer (which is a good thing!). A pin is an odd thing, so I assume it is probably an external unit. A backflow preventer prevents any sort of pipe burst from sucking potentially dirty water back into your potable water pipes. The pin they mention is probably to release the water from the mechanism. Normally this is a device on the hose bib itself (which would have no pin) so I suspect your setup is more involved than a simple hose bib.

As crip659 pointed out, this is for winterizing your pipes. Given the oddity of the backflow preventer step, my bet is this is a larger water line that goes to an out-building of some sort (like maybe a garden shed). It's also likely you're somewhere that gets truly hard freezes (northern US or Canada), where it's impractical to merely protect the pipes with insulation. Draining the pipes ensures there's no water sitting above ground, where it can burst your pipes.

  • Step 3 makes it pretty clear it's a hose bib, even if the backflow preventer is different than what you expect...Probably a vintage bib with an add-on backflow preventer.
    – Ecnerwal
    Jul 25, 2022 at 18:53
  • If the heat is off it doesn't take that hard a freeze to take out a pipe. Jul 26, 2022 at 5:07

This is for an outside valve that can freeze. Frozen water can crack pipes and valves. Destroying them.

An air bleeder will look like a small round knob sticking out of the side of the valve, under the handle.

These instructions are to make sure most of the water in the outside pipes/valve/hose bib is drained so it does not crack the valve or pipe.

  • 8
    Most likely (at least in my house) the valve with the bleeder is inside the house and supplies the outside valve. You don't want water in any outside valve. Jul 25, 2022 at 12:48

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