Yeah like boots said it's not the biggest deal in the world as long as they aren't leaking 24/7
Actually an easier step then calculating your actual flow per zone- while the zone is on, turn down the flow control control until the point of where you see the system loose flow to the point of the heads not spraying correctly, then back it off a bit so it's working.. Then turn off and on the valve and see if it's leaking.. Although this isn't telling you any numbers it does tell you that you have excess FPS going through the pipes
A proper way to check gallons per min is to write down the last 3 to 4 digits of your water meter, turn the zone on and run it for 2 min, write down your end result- then convert the cubic foot to a gallon
Using a
flow chartyou can see a 1" ( in this case) sched 40 pipe shouldn't be doing more then 16-18 gpm safely
So if you are doing 25gpm, this is more then likely your issue..
Install a pressure reducing valve and install smaller nozzle sizes to help reduce flow.