Backflow Prevention In The Home

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Hose bib with built-in vacuum breaker
Hose bib without a vacuum breaker
Without proper protection devices, something as useful as your garden hose has the potential to affect the quality and safety of the water in your home.   In fact, many of the nation's backflow incidents have involved garden hoses attached to hose bibs that do not have a vacuum breaker.


Garden hoses are very useful for a wide variety of jobs around the home.  Garden hoses are used for watering lawns, washing cars, and filling pools for kids to play in.  They can also be used to apply fertilizers and weed killers to lawns using sprayers that attach to the end of the hose or be used to open up plugged drains. 
Backflow can occur when there is a sudden drop in the water pressure.  This can be caused by a number of things.

Imagine what could be siphoned back into the plumbing system in your house if water pressure was lost while the hose was being used. 



Fortunately, it is very easy to protect the water in your home from backflow coming from a garden hose.  A hose bib vacuum breaker will provide an appropriate level of protection.  Some hose bibs have vacuum breakers built into them.  A vacuum breaker can also easily be added to a hose bib that does not have a vacuum breaker.


Vacuum breakers stop backflow by letting air into the faucet.  The air "breaks the vacuum," stopping backflow.  You can see how this works by making a hole in the side of a drinking straw then trying to use it.  It does not take a very big hole to stop flow through the straw.

All vacuum breakers have an air inlet.  Hose bib vacuum breakers will have either a series of small holes around the threads where the hose connects or a round cap covering up the air inlet.

Air inlet holes


Cap covering air inlet

It is not necessary to replace the hose bib to install a vacuum breaker.  A hose bib vacuum breaker can be added to a hose bib that does not have one.  The vacuum breakers can be purchased at a plumbing or hardware store for $5.00 to $20.00.  Installation is as easy as attaching your garden hose.  A plumber is not required for installation.  Each hose bib in the home should have a vacuum breaker installed. 

Vacuum breakers are not required on and should not be used on water heater drains, boiler drains, or clothes washer connections.

To install a vacuum breaker on a hose bib, simply screw it onto the hose bib until it is tight.  Then tighten the setscrew until the setscrew snaps off.  The setscrew prevents the vacuum breaker from being removed inadvertently.  The vacuum breaker can still be removed if it needs to be replaced.  A pipe wrench will easily remove the vacuum breaker.



When selecting a hose bib vacuum breaker to use on a outside faucet, the vacuum breaker must be a model that will drain automatically or that can be drained manually.  If the vacuum breaker is not drained, freezing can damage the hose bib.


This model drains automatically when

the garden hose is removed.

This model also drains automatically 

This model is drained by sliding the black ring up


This model is drained by pushing the white stem to the side.