How To Repair Anti Siphon Valve

Hello everyone,

Nosotros recently bought a new habitation and I take been inspecting the existing sprinkler system. The system currently has transmission valves and I wanted to upgrade them to automatic. Equally I began reading up more about valves and sprinkler systems, I noticed that the organization currently has anti-siphon valves installed. Now in all the instructions for anti-siphon valves that I've seen, information technology says the valves MUST be 6" above the highest sprinkler caput. Withal, in both the front k and the back yard (separate valves), there is at least i shrub sprinkler. The shrub sprinklers are 3-4 feet tall. The anti-siphon valve is no more than than six" above footing level, if that. Is this a botched job? Whenever I manually stop the sprinklers, I observe a rapid splash out of h2o from the outlet side of the valve. Am I right in assuming this is a backflow event being prevented by the valve? Should I remedy this situation? What are my options? I suppose I could raise the valve to in a higher place the shrub sprinkler, merely it seems like it would be weird to have this 5 foot tall valve upwards in the air against the house wall. What practice near people do in this situation? Should I simply cut down the shrub sprinklers? Or perhaps at that place are other valves that exercise non have this superlative restriction? Does that anti-siphon backflow preventer even so work or am I currently at risk of contaminating my h2o supply?

Thank you so much for any and all suggestions.

An irrigation newbie