You can install a different type of backflow device, such as a double check assembly or an RPZ. Both are much more expensive that a basic antisiphon, but neither have height requirements based on the height of the heads or outlets. Their only height requirement is in relation to the grade where the backflow preventer is located. Check your local codes.

All Wet

Hi tsunami,

I may be all wet about this, but I would think that you just need to be above your lowest sprinkler head by 6". As long as it drains away, it would act as a drain for your system and allow the suction to be broken by the siphon valve. I agree with "all wet" check with your local nursery or irrigation supply store. They would know the local codes. Let us know what you find out from the experts. Thanks Aloha.

Sorry Lehua, but all mfg.'s require their AVB's/ antisiphon valves to be installed at least 6" above the HIGHEST outlet, not the lowest. (PVB's are to be 12" above the highest outlet)Code will follow the mfg.'s recommendation. It is one of the basic rules taught in backflow prevention assembly testing training courses. I'm a certified backflow prevetion device tester and have taken the 40 hour course on two occasions. (The second after I let my original certification lapse)

All Wet

Oh just spring for the RPZ, last time I checked they were only a few hundred dollars or so plus installation (cough, cough).

i have same issue. can i just install the anti-siphon valve 7 feet up a wall? seriously.