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A drip irrigation zone basically has two special requirements: Filter and pressure regulator. You have to have a fine mesh filter to filter out things like tiny pieces of sand that can be in even municipal water sources that would clog drip irrigation emitter. Because drip irrigation uses punch-in emitters, you have a make sure the water pressure isn't more than 50psi, with 25psi being more ideal.

One of the ways to get going would be to dig up two of the three sprinklers and cap them off. Then replace the third with something like this: ( http://www.sprinklerwarehouse.com/1800-RETRO-Retrofit-Kit-p/1800-retro.htm ). That's the point at which you can connect drip irrigation tubing.

You can read over this information ( http://www.irrigationtutorials.com/dripguide.htm ) to learn more about drip irrigation.

A few other comments: Unless you do something other than the anti-siphon valve for backflow prevention, you'll have to make sure all the emitters for the drip irrigation system are 6" lower than the valve. The valve might also have to be replaced depending upon how much water the drip zone uses. Automatic valves usually have minimum flows required for them to operate properly. Drip irrigation typically uses much lower flow rates than normal irrigation. So it's possible that once converted to drip irrigation, the valve may not function properly. (Note, I installed a drip zone using a valve quoted as needing 0.2gpm minimum flow, but it's performing quite well, so far, running a circuit that is demanding only about 0.05gpm).

To properly consider your options, you need to first check local building codes (if you don't know where to being, perhaps start by trying to call the local building inspector) and find out what are the local requirements. Local codes can range from "install some sort of backflow prevention" to "you must install XYZ companies part #12345".

Assuming your current install of just anti-siphon valves is legal, then you're likely more toward the "install SOMETHING" side of the equation. In that case, your only options for have emitters above the backflow is an RPZ ( http://www.sprinklerwarehouse.com/FE860-100-Febco-1-Reduced-Pressure-Assembly-p/fe860-100.htm ) or a DC ( http://www.sprinklerwarehouse.com/FE850-100-Febco-1-Double-Check-Assembly-p/fe850-100.htm ). Note that some people consider DCs to only be marginal and completely inappropriate if you have a system that is injecting vertilzer (or anything else) into the irrigation system. But they can also usually be buried below grade in an irrigation box, so long as the test cocks can be properly accessed for testing. RPZ's on the other hand will sap about 15psi from your irrigation water pressure and must be installed 12" above ground.

Either one of these could be installed up-stream of the valves. Once you've done that, you could even ditch the anti-siphon valves and replace them with in-line valves that can be buried.


Now my worry is that you will look into how much it is going to cost to properly install backflow prevention and balk.


So if you are going to ignore suggestions on how to do it legally, here's another suggestion that I don't know how legal it would be, but at least it's better than nothing.


I don't see warnings on drip irrigation kits designed to connect to a hose bibb like you do on most plumbing and electrical parts (you know, the ones that say to check with local building codes and/or should only be installed by a certified plumber or electrician). So what you could do is install a hose bibb coming up out of the ground (like shown in the link to irrigation tutorials) feed by and located 6" lower than the anti-siphon valves. That's the part of this plan I don't know would be kosher with plumbing standards and building codes. But once you've done that, you could install a regular drip irrigation kit and use it's backflow preventer to protect the water supply from the emitters in the hanging baskets.

If none of the pipe or tubing is buried, it might not present a real toxic backflow danger. But then again, none of the drip stuff is figured as being for potable water, so decide for yourself if you want any water in it to ever be flowing backwards into your home. If you were really artful about it, you could find a creative way to have a vacuum breaker the required half-a-foot higher than any of the drip outlets.