here in Tenn. you do not have to have a seperate license to install irrigation but you must get certified to install a backflow preventor on you irrigation systems. we just sub out a certified plumber to install the backflow. not hard to do residential systems once you see how they are put together. we use rainbird equipment have hd very good success. they have an excellent website at
http://www.rainbird.com if i can help feel free to contact me at caneyvalleynursery@chartertn.net