expressed in millimeters per hour (mm/hr), this is the rate at which water is being applied by the sprinklers/sprays etc... It is a function of outlet flow and spacing of equipment together with the arc of operation. For example a sprinkler spraying 180 degrees will apply twice the water that the same sprinkler will apply over 360 degrees in the same time. Some sprinklers have matched precipitation rates by design.

The rate at which sprinkler heads apply water to a specific area of coverage, over a given period of time, measured in inches per hour.

The depth of water distributed on the ground over a given period of time. A typical precipitation rate for pop-up spray sprinklers is two inches per hour, about equal to a hard rain. Back to glossary index.

A measurement of water application which is given in the depth of water applied to the soil. Measured in mm/hour.