Sorry, I'm confused. I was looking at the supply plumbing meter at the street and turning the sprinkler system on. The supply water meter gave me cubic feet which converted to 9.5 GPM with 1 zone on and 18 GPM with 2 zones on.No part of a sprinkler system will tell you what the water supply is. You look only at the supply plumbing (meter, street pressure)
You measure flow and pressure simultaneously, and create a chart of different flows and the pressures associated with them. The idea isn't to run every possible bit of flow, unless you have a lawn that is acres in size.
Consider the possibility that the system was properly designed in the first place, as regards zone flow rates.
This post has been edited 4 times, last edit by "jmed999" (May 29th 2013, 7:43am)