Hose spigot vacuum breakers

[GL77]

I have a question about the vacuum breakers that screw onto the hose spigot, I'm just curious how they work really. Are they 100% effective at keeping water from backflowing? Can a tiny amount of water get through before it closes off? I know how important they are. I just don't really understand the mechanism they work by and would like to.

 

[Reach4]

They admit air, which breaks a siphon. A tiny amount could go backwards if the water pressure went away, but that would be from the top of the hose, not the far end. If your water pressure stays up, no backflow into your plumbing.

 

[Sponsor]

 

[LLigetfa]

Vacuum breakers do not provide comprehensive back-flow prevention. For that you need an approved back-flow preventer which is a double check valve.

 

[Quarterball]

There are two types used on outdoor hosebibbs/sillcocks/faucets. Most frostproof sillcocks have an atmospheric vacuum breaker and an integrated mechanical check back flow preventer. Screw-on hose thread vacuum breakers approved by ASSE 1011 utilize both an atmospheric vacuum breaker and a mechanical check. Most manufacturers websites have a parts breakdown drawing that will help understand how they work

 

[GL77]

Thanks a lot for the replies. I don't have the built in anti-siphon type of spigot and I can't change it out. I've been looking at vacuum breakers on Woodford's site and the price can vary from around $7 to almost $50 so there must be some quality differences! Does a better quality vacuum breaker mean safer water in the house? I've always had the cheap ones, I didn't even realize there were better ones available. What do I look for to get one that really works well without spraying water all over my wood siding? I have a lot of hoses set up for watering my yard and the thought of any of that water that sits in the hose getting into my drinking water supply really grosses me out. Do you have a particular one that you like to install, that you recommend?

 

[WorthFlorida]

What do I look for to get one that really works well without spraying water all over my wood siding? I have a lot of hoses set up for watering my yard and the thought of any of that water that sits in the hose getting into my drinking water supply really grosses me out. Do you have a particular one that you like to install, that you recommend?

Two ways to stop the spraying, keep the hose nozzle open when closing the spigot or wrap a rag around the vacuum breaker. I've done both. The spraying occurs because the pressure in the hose is higher than the atmospheric part of the vacuum breaker.

One purpose of the vacuum breaker is when a water is running through the hose without a nozzle and it's laying on the ground where the water is puddling. If the pressure feeding the spigot suddenly drops (toilet is flushed) water can then be sucked back into the home. The vacuum breaker prevents this from happening. It would be rare for a home on city water but a home with a well system could occur.

Threaded on vacuum breaker all all the same and mostly likely manufactured in an Asia country. If you want a better way, you'll need to install one at each spigot that will require a plumber if you don't have the skill and you're re not in a freeze zone. Or others suggested, frost proof spigots have built in ones.

https://www.supplyhouse.com/Watts-0792038-1-2-LF288A-Anti-Siphon-Vacuum-Breaker-Lead-Free

 

[John Gayewski]

If you really want to do it right a pressure vacuum breaker is what is normally used outdoors on a sprinkler system. They are approved for backflow and testable to be sure they are working 100 percent. If your installing something in the house for protection a pressure vacuum breaker isn't for you.