I live in a neighborhood in Houston, TX and share a meter box with my neighbor, although we have separate meters. In 1989 the neighbor's son decided to try being a sprinkler installer and put in his first system in my neighbors yard. I do not believe he put in a backflow preventer, as required. The house has been sold several times since that time. Whenever their sprinkler system runs, I get a loud constant noise in the pipes in my attic. It is especially loud when it starts, and when it changes...
