Hi Miguel, I am a fire sprinkler contractor in the Los Angeles area in need of the design, plans, and possible stamped approval of a new 4" inch fire line water service. For a new fire sprinklers system in an existing bldg. In Tustin CA. We are trying to find out if we can connect to the (what I believe is) 10" inch city main. I have a set of approved fire sprinkler underground piping ready upon request.