SPRINKLER TALK FORUM - You Got Questions, We've Got Answers

I have read the 2 year old posting in regards to water pressure and GPM and while it made sense, I am still having doubts in my design.

The pipe entering my home is 1", my water meter is 3/4", and the pipe after the meter that is servicing my home is 1". I get show 60 PSI from the facet outside the house with a 1/2" pipe connecting this to the 1" pipe servicing the rest of my home. My hose bibe is so low to the ground it's difficult to get a GPM reading. Also, from the many sources of literature I've read, the water presssure and GPM diminish from the resistance of the polypipe running out to the sprinkler heads.

I originally design my system by using a chart that lets you look up the pipe and water meter size and gives you the GPM. In my case that is 11-13 GPM. I have 10 Hunter PGJ rotor meters using a total of 13 GPM (1.3 x 10 GPM) in one zone. My neighbors, who had their systems professionally installed, have 3-4 rotors on a zone. I show 10 rotors.

Do I know what the PSI or GPM will be 100 feet from the valve box? What am I missing?

Also would you design to spray into/over an 8ft pine tree or up to it?