using anti-siphon valves

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mzimmers

mzimmers

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Hi all -

I'm getting ready to extend water pipes from the exterior of the house out into the yard. My house and yard are built into the side of a fairly steep hill. The challenge is, the only viable source to tap into is about 8' below the top of where I want to put my valves (it's on the exterior wall of a walk-out basement). I remember reading that anti-siphon valves are supposed to be 12" higher than any of the outlets -- true? An alternative would be to run pipes from the lower level up to the living level, and install one of the valves there.

Thanks for any ideas...
 
I'm not exactly clear on what the question is here. There are all kinds of "anti siphon" valves. Different ones need to be configured differently. They generally need to be set above the flood rim of the room/fixture they are in/near.
 
I think your talking about backflow protection,and which one to use, if all of your sprinklers heads are 12" or lower than the water connection coming out of your house,,you can use watts 802, it's called a pvb
I believe it's called a pressure type vaccum breaker
If you water connection is below your sprinklers heads after you come out of the house,you need a rpz,reduced pressure zone,backflow preventer watts 909 or watts 009
 
Hi Geofd - yes, backflow protection is what I meant. Those RPZ etc. valves are really expensive, plus they don't look like they can be automatically controlled, so I guess the best solution is to run PVC up and over, and install the valve there.

Thanks for the clarification.
 
Most sprinkler valves if not all, are meant to be installed at "curbside level", and if below grade, you will get residual water leaking from the valve. The control panel obviously can be mounted anywhere, provided you can access the wiring to the valve. Placing the valve inside a lower set room is a disaster in the making.
 
Well, then...I'm not sure what I should do. As mentioned earlier, this house is built into a hill -- there's a good 10' of rise from one end to the other. Are you saying that all my irrigation valves need to be at the "high" end of the house? If so, I've got a lot of work to do.

Perhaps a picture would help. This is the area under the deck which is at the same level as the house. (There's a workshop built into the area below the house.) The area under the window is the only place in the back of the house where I have a 3/4" water source. Do I correctly understand that the valve I've installed is not in a good location? I can run PVC up and across to deck level and install valves there, if that would result in a better installation.

IMG_0863.JPG
 
Yes, where your valves are installed, you will have constant drip down. You could install a one way check valve after the valve, which may work for awhile, but are prone to leakage after a few months due to hard water and constant use. My recommendation is to just run solid PVC lines to the upper portion of your property, place them in a buried sprinkler box, and run a set of wires to the sprinkler box, with the other end (your controller) close to a power source and away from weather.
 
Also, I have found from past experience, that the valves need to be protected from kids, wildlife and sun bleaching, so I recommend placing them all in a protective box.
 
mzimmers said:
Right, but one like this valve will work, right?
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mzimmers said:
Right, but one like this valve will work, right?
Click to expand...
No, looking at you pics were you come out of your house is way below your sprinklers heads, these devices must be plumbing board approved,and the must be a testable(by the city/town at least once a year, in mass it's a state law,I'm guessing California is pretty strick also,
You cannot put the wrong device in, that valve separates your drinking water from irrigation,water lawn chemicals,it prevents your drinking water from being contaminated
Click to expand...
 
This is really helpful (though somewhat daunting) information. Just so I'm clear on this, for a house like mine, which is built into a slope in both directions (north-south and east-west), do I understand that all valves must be (essentially) at the high point of the property?

The workshop has a bathroom, and there are some hose bibbs at the basement level...I'm guessing that these all need some backflow prevention, too?
 
Thank you for that. So, just to be clear: if I install this where the water exits the house, can I then put my valves there, too?

Also, is there a problem with running PVC on the exterior of a house? Other than cosmetics, I mean (this will be hidden).
 
Apples and oranges. Your sprinklers will still drain down and dump water at the valve. One last thought, Rainbird sprinkler heads sell a little bit more expensive sprinkler that has a built in check valve. That check valve MAY work to stop the water from draining backwards. I used them at my previous house where my valves were high, and the sprinklers were 10' lower. The first sprinklers would flood my lower patio until I found these sprinklers with the check valves. This kept the lines full of water when the valve shut down, and stopped the flooding of my lower patio.
 
mzimmers said:
Thank you for that. So, just to be clear: if I install this where the water exits the house, can I then put my valves there, too?

Also, is there a problem with running PVC on the exterior of a house? Other than cosmetics, I mean (this will be hidden).
Click to expand...
Since you are in California, PVC is fine buried, just make sure it is schedule 40, and not schedule 120.
 
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