Im studying irrigation in my spare time. I also have limited knowledge of past installs done by others. One in particular I'm using as my case study & I have a conflict. House has 55psi where the irr. mainline will ties in to the house mainline (1 1/4 Sch40 PVC). The irr mainline runs about 300 ft to the farthest zone. No hills. Calculating pressure loss I've determined that I need at least 1 1/4 irr mainline(SCH 40) for this distance. The install job they used 1" cl200 for the mainline. I just wanted to know what the general concensis is on this issue if you don't mind.