New member here, so hello and thanks in advance for the help.
Sorry for the long post, but i have what i consider a unique situation and need to provide all the details i can to get the most help from what i hope are some experts that can point me in the right direction.

I've got a small hunting cabin that i am staying at when, you guessed, hunting/fishing/getting away. City(rural)water is supplied to a frost proof yard hydrant just outside the cabin. From there, i run the water through a 50 ft rv garden hose to a hose bib(or whatever its supposed to be called)40 feet away. The bib connects to the cabin exterior wall. The bib is connected in the wall to a threaded fitting that connects to the 1/2 inch pex that is then used throughout the interior of the cabin supplying all the standard fixtures one might need to live (toilet, sink, water heater, shower, and kitchen sink). Under normal circumstances everything works perfectly with no leaks or problems and i have ok water pressure considering the long runs. At the hydrant there is great pressure, i don't know the psi, but i can fill a 5 gallon bucket in about 20 seconds.
The problem is, at the hydrant i have a "Y", 1 side is the hose supplying the cabin, the 2nd side is used for general outdoor uses. Whenever i use this 2nd side, the bib connections just inside the flange screwed to the cabin leaks like crazy. It's like the system is back pressuring or something, even though, by right the pressure should not be increasing. I am no plumber so i am at a loss. I have tried multiple scenarios of shutting off the supply side on both ends, just the hose bib, i even shut off the shut off inside the cabin. Prior to the hose bib that is there now, i had a frost proof sillcock and same thing leaked like crazy. I removed the frost free sillcock and replaced it with a normal hose bib and turned it around also so the shutoff is outside instead of inside hoping that would cure it but nope. My only current way of dealing with this is just unhooking the 1st side completely and doing whatever i need to do with the 2nd side, then when done, hookup the main line and off i go again, but that is a real pain.
Every threaded connection is taped and again, under normal conditions when not using the 2nd side of the "y", everything is great.
I didn't lie, long post.
Any ideas???

The leak is from a taped, threaded pipe connection? Can you post pictures of the inside and outside bib connections and where it's leaking from?

How to post pictures - [www.plbg.com]

vacuum breaker actually working as intended



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"Measure Twice & Cut Once" - Retired U.A. Local 1 & 638

Unfortunately i don't have pictures at this time, and i live 90 miles away from the cabin. With the the original anti siphon sillcock i had there it leaked right out the handle stem which was actually inside the cabin. Now i have the regular ole hose bib, i only know that it leaks from right behind the flange that screws into the siding. i trust the connections as under "normal" conditions all is well.
thanks for the quick reply

please don't laugh
Vacuum breaker?

On a typical hose bibb on a home, they will install a vacuum breaker. It makes it impossible for a condition to occur that would cause something to be siphoned into the potable water system. When you use the second half of your "Y", you create a venture or vacuum. At least that would be the "educated guess".Put inline valves at the "Y", and close the one to the cabin when you want to do things outside.



Edited 1 times.

the y does have shutoffs for each side, and i shut off the main and the one at the bib. Maybe i should not shut off the bib, only the 1 at the y?
So is a vacuum breaker the same as a check valve? i was researching, and rv's and campers use a check valve at their city water inlet. i wonder if that's what i need??

Quote

the y does have shutoffs for each side, and i shut off the main and the one at the bib. Maybe i should not shut off the bib, only the 1 at the y?
So is a vacuum breaker the same as a check valve? i was researching, and rv's and campers use a check valve at their city water inlet. i wonder if that's what i need??

a vacuum breaker is NOT the same a check valve


simply shut the 'y' valve and not the bib itself

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"Measure Twice & Cut Once" - Retired U.A. Local 1 & 638