I have this device on my outdoor water faucet. It is leaking water in all directions and by leaking, I mean pouring water everywhere.

What is the purpose of this device and how can I remove it so I can replace it if it is needed ? I don't have an in-house winter valve, so I'm guessing that it has some usage for winter.

I tried to remove it using a vise-grip but to no good.

Two metallic joins that seem connected together

Water pouring out everywhere

  • I'm no expert here, but I really think you should call your city for that, cause I'm pretty sure that it's their problem and they will come and fix it for you.
    – user13586
    Jun 21, 2013 at 14:30
  • The city isn't responsible for anything after their shutoff valve, which is often co-located with the water meter near the street.
    – BMitch
    Jun 21, 2013 at 14:56
  • I'm telling him that cause for me, the same problem, the city came to my house and changed everything free of charge.
    – user13586
    Jun 21, 2013 at 15:00
  • It is true that I could call them. Too bad I read your answer on a friday afternoon when all town office are closed and that we have an holiday on Monday. But I got a plumber to inspect the device. Won't cost that much and I will have a completely new water faucet and not just the backflow fixture. Jun 21, 2013 at 17:57

2 Answers 2


Backflow preventer: The fitting closest to the faucet MUST unscrew CCW.

Looking at your bib at the house siding, its not secured. Use a second wrench on the faucet, torquing in the opposite direction to the wrench on the backflow adapter. This will prevent you from busting the water pipe and REALLY making a mess. Backflow article

  • 2
    Feel around the side of the fitting that is closest to the house that you can't see. Some are held in place by a small allen head set screw
    – mikes
    Jun 20, 2013 at 20:22
  • 1
    We called a plumber. Effectively, I don't want to cause a breakage in the piping in the basement ceiling. I need to repair this because we are getting a new pool and I don't want to fill the pool with that much water being wasted. Jun 20, 2013 at 21:57

Leaking Add-on vacuum breakers or backflow preventers often are non-removeable per municipality mandate, they're installed with snap-off head setscrews that permanently mates the threads to the hose bib.

enter image description here

Since they're meant to be a permanent fixture, if they were removable, due to corrosion, they now aren't unless you're willing to apply some heat to the vacuum breaker and a chunk of ice to the faucet to get a little differential expansion going to break them loose. You have to do this without cooking the packing around the valve stem, or you have yet another problem leak.

Given the age and crustyness, you'll be replacing the faucet soon anyway, so go for the permanent solution which is to install a frost proof faucet with built-in vacuum breaker and choose a quality manufacturer like Arrowhead or Silcock who has replacement parts available.

enter image description here

  • I just found a cool video that shows how to saw off an old vacuum breaker whose setscrew was broken off: youtu.be/09yc1VSVZck?t=1m35s
    – Ryan
    May 29, 2017 at 15:49

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