Question
The pressure on my front lawn sprinklers has dropped significantly over the last year or 2 and I need help trying to figure out why. Here's some background:
1. My house has high water pressure
2. I have 4 zones. 2 in front, 1 on side, 1 in back. My main in front is low for sure, and the 2nd in front might be a little low as well. Side and back are fine.
3. All 4 run off the same supply line from the house, and this is fully opened.
4. I thought the issue might be with a clogged controller valve. So I replace it but no change in pressure.
I thought there might be a leak at one of the sprinklers. So I dug around them and dont see any leaks.
5. I tried capping the sprinkler heads one by one to see if I could spot a leak below the ground (if the dirt in the hole got wet, then I knew there was a leak there somewhere) and didn't see anything.

I am assuming that I have a leak somewhere. What ways can I use to find it other than completely digging up my lawn?


Answer
Hey Andrew, normally if you have a leak as bad as you describe, all you would need to do is  let the system run for awhile and the water will show up on top of the ground. When I first read your problem the first thing I would have suggested was to replace the diaphram in the valve, but you say you already replaced the valve. It sounds as though maybe you have a restriction in the pipe, and maybe not necessarily a leak. What I would suggest, is to turn on one of the valves that work good and then go look at your water meter and calculate how many gallons of water are being used while the system runs for a minute. To do this, simply turn on the valve, and then as you look at the water meter you will notice a dial that goes in a circle, with numbers from one to ten. If the dial goes from 0 to 8 in one minute, that means you are getting 8GPM (gallons per minute). Lets say the good valve you are getting 20 GPM, but the bad valve you are only getting 10GPM. This means that either the valve is not opening up all the way, or you have a restriction in the pipe somewhere in the line. Good luck and let me know if you need anymore help, have a great day.