1. Turn on your irrigation system, one zone or station at a time. Locate and mark sprinkler heads. 
2. Turn the irrigation system off and distribute catch cups in a grid pattern across the zone. — A good rule of thumb is to place a cup near each head (not obstructing spray), and halfway between the heads. 
3. Turn on sprinklers in the zone of interest and allow to run for twenty (20) minutes. 
4. Take note of how much water has collected in the catch cups.
5. Take note of differences in each cup. Cups that contain less water indicate which sprinkler heads may require adjustment or maintenance to improve the uniformity of watering. Visit utahwatersavers.com and slowtheflow.org for more information.
6. Add together the amount of water collected by each cup and divide by the total number of cups. This will give you the average amount of water collected in twenty minutes. To get the average amount of water applied per hour, multiply the previous number by three. Example: (0.1+0.1+0.1+0.1+0.1) / 5 = 0.1 inch of water per 20 minutes — 0.1 x 3 = 0.3 inches per hour

Now that you have your sprinkler output in inches/hour, you can set your irrigation system to run based on your lawns water requirement as determined by local temperature and precipitation. Use the chart below as a starting point to determine how many irrigation cycles you should set your clocks to run each week, given the results of the catch cup test.