Rotating Sprinkler Heads

If you use rotating sprinkler heads to water your lawn, you usually have to run them about three times longer each cycle than pop-up sprinklers to apply the same amount of water. The Water Authority recommends watering grass using the cycle and soak method.

For example, instead of the typical recommendation to use three cycles of four minutes each, you may need to run rotating sprinklers for about 12 minutes during each cycle.

If your roots are shallow, you should put down about a third of an inch of water with each watering. If your root system is deeper, you can put down more water at one time and water less frequently.

To find out how much water your sprinkler puts out, check with the manufacturer. Many manufacturers have this information on the Internet.

The performance of sprinkler heads depends on many variables, including the pressure and design of the system. For a quick test of your sprinkler system's output and efficiency, try the "six-can test."

Testing your system

Follow these steps to test your sprinklers to see how much water they put out:

1. Put six tin cans of equal size scattered on the lawn. (Empty tuna or soup cans work well)
2. Run the system for 10 minutes.
3. Combine the contents of all six cans into one.
4. Insert a ruler and measure the water depth. The depth of the water indicates the rainfall equivalent in inches per hour.

Most big rotors apply about one-half inch per hour. You should see a similar amount of water in each of the six cans before you combine them. If some cans have more water than others, it means your sprinkler system is not very efficient and may benefit from adjustment or repair.

During the test, watch closely for run-off. Although it is alright to have run-off when you are testing and adjusting a sprinkler system, it could result in a water waste fine during normal operation. Make a note of how long the system can run before run-off begins, then set your cycle times several minutes shorter. If you want additional technical information on sprinkler scheduling, visit the wateright.org Web site.