This water faucet is on the wall outside of my house. As shown in the following video, when gradually turned on, it leaks from the above. It is as if the green hexagonal cap is not sealed due to missing part. If turned on enough, the water stream can become quite forceful that it can hardly be described as only "leaky". I forgot when i first discovered it if any part under the cap accidentally came off and got lost. I don't recall noticing any. I don't know what the part from where the water stream is leaking out is called. What part do I need to buy to fix it? Do I need to replace the entire metal faucet?

video that where and how the leaking happens: https://photos.app.goo.gl/1DdiSeGceGRhfjVu6

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  • the device on top is a vacuum breaker ... it prevents water from being sucked into the watet system when pressure in the water system drops .. a small cylindrical plunger with a rubber ring is missing
    – jsotola
    Commented Jul 29, 2022 at 20:32
  • Think it is an anti-siphon device. It should unscrew from the faucet and you can take it to a local hardware/plumbing store for a replacement.
    – crip659
    Commented Jul 29, 2022 at 20:32
  • something is missing (the rubber part) unless you took it out, or it is still in the cap
    – Traveler
    Commented Jul 29, 2022 at 21:09
  • I see you have the rubber seal, pulled down. Pull it back up and stuff it in the nut
    – Traveler
    Commented Jul 29, 2022 at 23:10

1 Answer 1


You appear to be missing at least one part.

It's a vacuum breaker, they are quite common and usually standard - a hardware or plumbing store should have a replacement (either the whole set of parts, or the missing part(s) - the former is more likely.)

Typically you have the cap (the green bit - which does not and should not seal), the body (the white bit), and an o-ring sealing the white bit where it connects to the metal (which can crack & leak, and is either hidden under the white bit or missing) as well as a part that should be getting pushed up by water pressure to seal the hole in the center of the white bit (which is clearly missing. Since it's not held in place by anything, and small, it's commonly lost when disassembling the valve if not paying careful attention.)

Replaced a cracked o-ring on one of mine this spring, as it happens.

There should be no need to replace the whole metal valve. Just the plastic vacuum breaker (also called anti-siphon - means the same thing) assembly.

  • 1
    If you cannot find the parts you may be able to purchase a new faucet and part it, much less work then replacing it. If you find the parts get a spare and I would hang it from the pipe in the basement that feeds that valve. Otherwise place it some place you will find it when needed.
    – Gil
    Commented Jul 30, 2022 at 20:27
  • 1
    If you can't find the parts you're not looking terribly hard, according to the search results I get from sillcock anti-siphon valve replacement - no need to get a whole spare sillcock you'll have to store and then not be able to find, or not remember you have...even the borg has one, and they are relatively terrible for plumbing parts. sillcock vacuum breaker replacement also works fine.
    – Ecnerwal
    Commented Jul 30, 2022 at 20:38

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