This came home to me in a big way when my weed guy came around to spray. He was filling his tank with water from my hose and mixing in the various chemicals he uses when the power died. The pump shut off and the back flow prevention device on the hose he was using did what it was designed to do; dumped water on the ground that might have made it back into the house water. Now, there was no real danger because he had the fill device on his tank set up properly to prevent back flow and I had a vacuum break (back flow preventer) at the end of the hose, however it does illustrate that something can happen when you least expect it. There's been many times I was filling the pool after doing something that the power could have failed and caused a siphon effect to suck water into the house supply. So, you need these things.
Where I live you have to have a functioning anti-siphon device on all hose bibs before you can pass inspection to move in. However, almost everyone uses one of these:
They do the job just fine.....,but (remember, there's ALWAYS a but), they cost around 4-5 bucks and fail in about a month in the desert heat. There are also plastic ones that cost a little less, but I've had them fail in as little as a week. The construction is the problem with these. They have a nylon support, metal spring and soft plastic or rubber diaphragm inside. The nylon support will dry out and crack, the spring loses tension, and the diaphragm dries out and leaks. Also, at low flow levels, the diaphragm will vibrate and cause a loud squeal that will drive you nuts. I have personally changed out about 10 of these things over the last few years and have a couple of faucets that I just left them off of when they darn things failed. To add insult to injury, many plumbers will attach these to the faucet and tighten up the little set screw so you can't remove it. They actually break the set screw off so it won't unscrew. This means you have to force it off with a big wrench probably ruining the threads in the process or replace the faucet and vacuum break device. I really can't blame the plumbers for doing this. They put them on to pass inspection and someone comes along and unscrews it which causes the plumber a call back and costs money. You can't repair these things, they're cast brass and don't come apart, and plastic ones break when you try to take them apart.
So, what to do? There are a number of possibilities including a vacuum break for the whole house, but each of the solutions has a drawback that I hate. For example, the whole house idea will work, but I'll have to drain my house plumbing if there happened to be a problem. I think I have found a solution to this. Arrowhead Brass makes a nice anti-siphon hose bib that isn't too expensive and seems to do the job just fine. Their web page here shows the different styles, and for you folks that live in cold country they even have the no-freeze designs. I bought three of these:
Yes, they cost a little less than 14 bucks, but they compare favorably with a hose bib and the vacuum break purchased separately. What's really, really nice about these is that they don't leak water every time you move the garden hose. See, the water hose holds water in it and when you grab an end and wander over to water some plant the water flows backwards through the hose and sprays out the vacuum break making a mess on your patio. This can be a problem if the bib is over a nice redwood deck or next to a patio table. They don't make noise at low flow levels and only purge water if the valve is actually open. Just about everything you could want in a vacuum break faucet combination.
One suggestion for you folks that decide to try one of these, use pipe dope instead of teflon tape when installing it. I used teflon tape and the darn thing leaked at the threads; when I pulled it off, cleaned it and used pipe dope, there was no problem at all. I don't have enough experience to tell you how long they will last. Mine have only been in place a week and that's not much of a track record, but they can be dismantled and repaired which is a plus in my book
Its July 2016. How did your Arrowhead faucets hold up? Any squealing or other problems?ReplyDelete
These little beggars have been out in the Arizona sun, the freezing winter here in the foothills and operated a lot. I haven't had any problem at all, they still work exactly the same as when I installed them. They never make any noise and they don't freaking leak.Delete
Actually, I have a couple more now, all the frequently used faucets outside are these now. I don't even think about the cheap anti-siphon devices anymore, new outside faucet, I just order another one of these.