Thanks guys, I think that answers all of my question. I know that my City requires a DC valve assembly, but I'm hoping that they'll let me go with a RPBA in lieu of it since I want to use a fertilization system. As for my parents, I'll probably see if they're willing to add a DC valve upstream of the anti-siphon valves, but anti-siphon was all their city required and they work for their setup.
As a side note, if I were to want to install a fertilizing system onto the sprinkler system, I would need to upgrade to an reduced pressure backflow, right?
Thanks for the info (I've used that link a lot, I like the information they provide). I'll have to talk to the City and see if they'll accept Anti-Siphon as an equivalent alternative and if not, I guess I'll put a filter upstream of the DC Valve.
Thanks! I'm also about to setup a new system where the double check is required by city law. Would it be a good idea to put anti-siphon valves on each of my zones? Your comment makes me thing that DCs aren't all that great.
I currently have some Rainbird Jar-Top valves that have built in anti-siphon valves. They're working fine, but I know that over time they can loose their effectiveness so I was thinking about putting a double check valve assembly (from home depot or Lowe's) where I tapped the mainline for the irrigation system. Is there anything wrong with doing that? I mean will the DC interfere with the anti-siphon valves? Do the anti-siphon valves add any extra level of protection if they're down stream of a ...
