Hi what's up! Searching didn't help much because alot of the lingo went over my head because I'm not a pro. I'm building a sprinkler system for my house. Plans have been drawn up by Rainbird. I have a few simple questions before I start: 1. I'd like to use inline valves because it would look much nicer to conceal the valves in a box in the ground. But the valves that go above ground (the anti-siphon valves) have the anti-siphon feature. I gather that the anti-siphon device prevents contamination into my house line via backflow. Is that correct? 2. Could I just use inline valves and use a backflow preventer instead of anti-siphon valves? What does a backflow preventer look like? Home Depot didn't have any on the shelf - where would I buy one? Where would I mount it in the system? 3. Using inline valves, how to you connect them so that you can take replace a valve if it breaks. . .is there a way to set it up so you can unscrew the pipe from the valve or something so its not so permanent? 4. Lastly, I live in northwest Louisiana and it doesn't snow or ice up here but about every couple years at best, but it does get in the upper 20's oftentimes. Do I need to install drain valves or even worry about the pipes breaking since they will be below the soil? I know this is lots of questions. To make it easier, just type the number your responding to if it will help. Thanks a million in advance!