Had two seperate proposals on residential irrigation systems. One recommended placing the backflow preventer under my house crawl space. (ease of winterizing and freeze up prevention). The other of course recommended outside installation. (Preventative measure in case of backflow, as well as ease of maintenance). Which is the proper way..or are the advantages.
I always install a PVB outside right from the point it comes out of the house. It is easier to install, winterize, and maintain. Take caution though, when it freezes, make sure you put a blanket or towel on it to keep it from freezing.
here in Wyoming the city code of most citys is that a double-check
valve is used so that city or county can tie in to see if it is working properly and loacation is next or close to main water turn-on