The simple test below will show you if your sprinklers are delivering efficient / consistent coverage or if they are over watering in some areas and under watering in others.
To check matched precipitation coverage within a certain valve zone, place identical-size cups, more or less evenly spaced, throughout the area watered. The cups should be between 5 and 10 feet from each other.
Keep the cups at least 3 feet from any sprinkler heads, if they are closer than that to a sprinkler you will get inaccurate results, also keep the cups at least 12" from the edge of sidewalks, curbs, patios, or other paved surfaces.
Run the sprinklers for a few minutes so that the cups are at least 1/4 full, if you have rotors the slowest moving one should make at least 5 passes over the cups.
Now compare how much water is in the cups. When the sprinklers are properly adjusted each cup should have about the same amount of water in it.
Setting Up A Coverage Test
Shows The Results Of A Properly Tuned System
Shows The Results Of An In Efficient System With Inconsistent Coverage