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

At this point, the blame game (no mater where it leads) isn't going to get anything fixed in this situation.

While not cheap, the quickest and easiest solution for your popup zones could be Dan's suggestion of the MP Rotators. They are basically replacement nozzles (so you don't have to dig up the pop-ups) that convert a spray to a rotator. Once set for a 12' half circle spray pattern, each will use only about 0.5-0.6 gpm. For a 16 head zone, that can be as little as 8gpm. Now they are not cheap (somewhere in the neiborhood of $7 each). So if you've got something like 50 heads, that's going to be about a $400 upgrade. So I would suggest that you get enough MP Rotators to replace all the nozzles in the zone with the fewest head. That will be less than a $100 test and could solve your problems. If so, then suddenly the ease if this fix will be more than worth the $$$.

With a zone of 16 half-circle sprays, you can always close down the nozzle adjusting screws, one head at a time. At some point, you should get good performance from the working sprays, and you can use that for establishing a flow rate you can work with.

By the way, there is a chance that there is a partially closed shutoff valve in the meter pit, or elsewhere, and that should be eliminated as a possibility.

I'd like to make one suggetion if you're going with the MP Rotator. I'd buy just enough for one zone at first. Like hkd said, these aren't cheap. I've had problems with these trying to solve issues similar to yours. The MP Rotator nozzel itself needs a certain amount of pressure to pop up before it will function. If they don't pop up then they'll work worse than what you have now.