Every winter, and depending on where you live maybe even before right now, you must winterize your exterior hose bibs. That demands that you turn off the handle of the interior valve which services each hose inside. Then you must open the handle of the hose bib outside. And if you loosen or remove the cap of the bleeder valve inside it will break the vacuum inside the pipe and drain any water out.
Let me show you a picture.
The little bleeder valve is seen on top of the copper pipe just under the black and white drain line.
The blue handle, somewhat hidden behind that pipe is the turn-off valve.
If you turn it off..
oh, oh, wait...
That valve services the dishwasher.
It's the right one to use for a hose bib shut off, but not necessarily for a dishwasher.
And that tube is the hot-water tube and services the kitchen sink with hot water.
AND the hose out back... on the deck... and there's no shut-off for the hose even though it's hot water.
Did they really want to use hot water for the hose out back? Gee, maybe this wasn't the most instructive example of how to winterize... (;>)
Well, in the winter, before it gets too cold, you want to do what I said above for all your exterior hose bibs. And this one? This one will just have to be thought about again... And good luck with it!
My recommendation: Winterize your hose bibs every fall so your pipes will not freeze and break. Plumbers count on your not doing that! And if your pipes break it is a huge mess.
As to the other kind of mess above, well, welcome to my world!