What’s the deal with Backflow Preventers for Outside Faucets?

Posted on by Andrew LeVahn

Outside faucet backflow preventerOutside faucet backflow preventer

  Back Flow preventers that are commonly seen on outdoor spigots

So what is that thing that is at the end of your hose spigot that’s leaking water all over?

Back Flow preventers are devices that are often times added on to the end of a hose spigot. The purpose of a backflow preventer on a garden hose spigot is to prevent tainted water from entering the drinking water system. Let me explain it like this: If your neighbors house is on fire and there are firemen using fire hoses to put it out, the amount back pressure needed could actually suck the dirty water out of the bucket your using to wash your car. If there was no back flow preventor on the line our clean drinking water could be compromised. That is why they have made it code in the state of Minnesota to have a back flow preventor on your hose spigot.

All of this makes sense and seems logical. What isn’t logical and does not make sense is the fact that most of the time a back flow preventor is put on in a way that it’s not meant to be taken off again. This makes it very difficult to repair or replace a back flow preventer when they start to fail. Like most things in this world a backflow preventer will break down over time. It will either start leaking or in some cases it won’t let water even through the hose spigot at all.

In most situations back flow preventers can’t be repaired. There are dozens of manufacturers that make back flow preventers and unfortunately each of them is unique. The same company can have a variety of different models. Because things are so unique there isn’t many parts available to repair them. This means that in most cases you need to actually remove the whole valve and replace it. I say the “whole valve” because in many cases when attempting to remove the back flow preventor only a portion of it comes off.

When attempting to remove the back flow preventor make sure that you have any set screws removed that may be holding it in place. Also if you are going to use a wrench make sure that you have a second wrench on the spigot itself so that you are not putting too much pressure on the solder joints in the wall. The last thing you want to do is to break a pipe in the wall and have a flood inside the house.

Mansfield Frost Free Anti-Syphon valve

Mansfield Frost Free Anti-Syphon valve

If worse comes to worse (which is often the case with plumbing jobs) and you need to replace the valve because you cannot remove the leaking back flow preventor, make sure to call a professional to replace it (for instance you can contact us. Call 763-551-8990 or check us out at http://www.levahnbros.com/plumbing.html ) You may also want to consider putting in a different style valve. For instance Mansfield makes a valve that has the back flow preventor already installed internally in the valve itself. Best of all you can purchase replacement parts if the Mansfield valve fails. It’s a great valve that also serves the purpose of being a “Frost Free” valve. This means that the shut off for the valve is found at the back of the valve which is located inside your house. Having the shut off inside the house means that there is less of a chance of your hose spigot freezing and bursting in the cold.

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You may also want to check out these posts related to hose spigots and frozen pipes:



For more information on what to do or for product info/purchase come in and see us at 12700 Bass Lake Road in Maple Grove Minnesota

Visit us on the web at http://www.levahnbros.com

About Andrew LeVahn

I am the fourth generation of LeVahn's. I have been working at LeVahn Bros. since 1994. I went to Minnehaha Academy for high school and Bethel University for college. View all posts by Andrew LeVahn → This entry was posted in Frozen pipes, Pipe Leak, Plumbing, Uncategorized and tagged , , , , , , , , , , , , , , , , . Bookmark the permalink.

4 Responses to What’s the deal with Backflow Preventers for Outside Faucets?

  1. Pingback: Are there supposed to be fingerprints and watermarks on KOHLER kitchen faucets brand new in the box? | Kitchen remodeling Solutions

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  3. Wil C. Fry says:

    These things are so frustrating. The ones on our house prevent using the hose at lower pressure (trickle). If you try, water only comes out at the spigot instead of the hose. And today, it wouldn’t even work at normal high pressure — just sprayed out the backflow holes instead of going through the hose.

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