Feedback on Setup - Need Help with backup preventer

I just installed my zones and backup preventer. I went with Rachio Gen3, 2 Orbit [3-Valve Inline Manifold Assembly](http://3-Valve Inline Manifold Assembly) and Orbit Anti-Siphon Valve

My only problem is my backup preventer keeps spilling over. I’ve read a lot about this and people say this is normal. Some say you don’t need one. My problem is I am going up hill from my water source. Below it what my setup looks like.
My questions are.

  1. Should I remove the backup preventer or keep it and figure out what is going on?
  2. Did I do my setup correctly. Should I change anything?

Would love some feedback. Here is what it currently looks like.

So the anti siphon valve you have is meant to directly feed water into a sprinkler zone — not as a backflow valve for an entire system. See

“1. Never install an anti-siphon valve upstream of any other valve. If you do the anti-siphon valve will not prevent backflow and you have wasted your money buying it. (Exception: drain valves are OK installed after an anti-siphon valve.)
2. Never use an anti-siphon valve as a backflow preventer installed on the mainline upstream of other valves. This is a common error that a lot of people make. I have heard employees at home improvement stores recommend installing an anti-siphon valve as a backflow preventer with standard electric globe valves installed after it for each of the sprinkler zones. I have seen many contractors do this also. Both should know better! Don’t you do it!!! It will damage the anti-siphon valve. Plus the anti-siphon valve will not prevent backflow when installed this way. You are no better off than if you didn’t use a backflow preventer at all. (Contractors and suppliers: before you flame me for being wrong, do some research. Don’t embarrass yourself! Most anti-siphon valves have a warning on the box or in the installation instructions about this. Just read the instructions!)”

Others will chime in but I’d recommend using a different type of back flow preventer — the irrigation tutorial webpage has a decision tree on deciding what type to install.


Thx. So just get rid off it. Got it. Anything else I should know or change with my setup?

Like @Kubisuro said, that is an anti-siphon valve, not a backflow preventer and not meant to be used in front of other zone valves. You can install one of two ways.

  1. Leave the existing zone valves as they are and replace the anti-siphon valve with a backflow preventer. This will be a larger brass unit, and if you go with a Febco unit, you might be able to get it to fit close to the footprint of the current anti-siphon valve. The Zurn/Wilkins usually have a larger footprint.

  2. Forgo a true backflow device, but you will need to replace all the zone valves with the anti-siphon valves. The thing I don’t like about using anti-siphon valves is that they spill a small amount of water out each and every time the zone runs. Anytime I have seen an install using anti-siphon valves, the area around it is constantly damp. Being that this is near your foundation, I’d stay away from this option, IMHO.


@tmcgahey and @Kubisuro How does this setup look? Am I missing anything?

Ummm, is the top valve being used as a master valve? Right now it doesn’t look like you have any type of backflow prevention in place.

Like I said earlier, your options are to:

  1. Leave the lower 3 valves in place, and replace the upper anti-siphon valve with a true backflow device. The Febco might be a better option in your case because it has a smaller footprint than the Zurn/Wilkins unit.

  2. Replace the lower 3 solenoid valves with anti-siphon valves and remove the upper valve (assuming that is an anti-siphon and not a master valve).

Without completely repiping your whole setup there, I’d recommend the first option as I think you could probably fit that closely into the existing footprint.

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@chadholdorf, @tmcgahey If you are going uphill from your water source in the picture, a pressure vacuum breaker (PVB) would be lower than the highest head. A PVB has to be at least twelve inches higher than the highest head because it can’t take any back pressure.

You’re going to have to install a double check assembly (DCA) or preferably a reduced pressure principle device (RPZ).

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Good catch! Totally missed the uphill part! I’m a flatlander, so not the first thing on my mind…