Simple / cheap catch cup test

Installed an R3 a few days ago and wanted to do a catch cup test. Cheapest solution was Solo plastic cups, which were less than $5 for 25. I put a 1/2" nut in each to add a little weight and seated them down in the grass a little and they worked great.

The diameter of the cups were 95mm, so a little smaller than normal catch cups, but found 20 min runs filled them enough to measure accurately.

I also found a much easier way to measure the volume. Instead of rulers or graduated cylinders, I used my kitchen scale which measures to the closest gram. I zeroed out the scale with an empty cup/nut and then was able to get direct measurements without subtracting the weight of the cup.

Converting to mL is also super simple: 1 gram of water = 1 ml of volume so no conversion is needed. Simply use the measured weight as the volume.

Most advice for testing with catch cups suggest putting a cup about 2 feet from each head, then adding more in between. This seems like poor advice as close to the sprinkler head water is spraying mostly horizontal and/or a little upward. Cups that close to the heads won’t catch most of the water, with it mostly hitting the sides of the cups (regardless of type), but should be included in the measurements.

I opted to spread out my cups so they were 5 or more feet away from the heads. In my front yard I ended up with 71% efficiency/uniformity. My first test with them closer together gave me much lower numbers.


Great post. I used some cat food cans from a neighbor that has cats.