Anti-siphon valve needed?

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jakeotr

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Hello...bear with me..this may be long, but I want to try to describe everything. I have an anti-siphon valve in my water heater shed that runs to a remote hose bib in the backyard. It has started leaking. I bought some replacement parts and then started wondering if it should be there at all. It comes off the cold water line running from the house, the shut off valve for this is about 5 feet above the siphon valve which is about 1 foot off the ground. The outlet then runs underground thru flexible plastic line to a shed with a hose bib. I have since remodeled this shed and ran water lines to a sink and installed a hot water heater on the second floor (shed is built like a little barn). The problem I'm having is that the instructions for the backflow valve clearly state that there should be no shutoffs down stream and that it is not rated for continuous pressure. So it looks like it shouldnt be there at all, but I would agree that, because of the plastic line running underground, it needs some sort of protection from possible contamination due to leaking/cracking etc. So do I need a backflow valve or can I just plug it off? Is the line running to the shed just considered an extension of the house plumbing even though its not solid line? One other issue is...instructions state the backflow valve be 6 inches above highest downstream piping, which obviously cant work in my situation since the water heater in the shed is on the second floor. Please help, thanks
 

Jimbo

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Hose bibbs need back flow protection. Just what the actual code is in your area, you will have to ask.

The easies thing is to replace the bibb itself with frost proof bibb with built in backflow.
 

jakeotr

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There is no back flow proctection for the hose bibs coming out of the house, so I wonder why the builder decided to run one under the backyard? Also there is much more plumbing in the shed coming off the incoming line now...what do you think?
 

Jadnashua

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The thing with anything with a hose on it is that the outlet could be sitting in polluted water or any substance. A sink, toilet, or any other properly installed device can't be sitting in water, so doesn't need the backflow preventer (vacuum breaker is one type). In most places, all hose bibs should have a backflow preventer as should a toilet fill valve.
 

hj

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From what I can determine from your description, you need a backflow preventer, but that one is the wrong type. If I interpret your situation properly, you need a "hose vacuum breaker" on the hose faucet itself. Your BFP is to turn a lawn irrigation system on and off. And that is the ONLY thing that version should be used for, although they are often misused for other purposes.
 

jakeotr

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Thanks hj for the answer....just to clarify....I dont need the backflow valve at the house, for the plumbing in the outbuilding, and I should just plug it off? The hose bib at the shed rarely gets used and can use a screw on type. Funny thing is, the backflow valve, not being rated for constant pressure, has lasted at least 10 years under pressure!
 

Jadnashua

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In some places, that backflow valve for a sprinkler system, would require annual recertification. The fact that it passes water does not mean it is working.
 

jakeotr

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OK...forget I have a hose bib on the shed...I'm taking it out. Do I still need a backflow valve at the house for the water run under the backyard?
 

hj

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The BFP is ONLY for a secondary system, such as a lawn irrigation installation. Not being rated for a pressure system is related to how it works, or rather would not work when needed, not whether it will leak or not. The legal definition is that any water AFTER the BFP is NOT potable water, and is considered to be subject to contamination, which is why it NEEDS the BFP valve in the first place.
 
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