Irrigation systems work by moving stored water through a system of pipes and sprinklers to provide the moisture plants need for growth. Lawn irrigation systems use timers and electronically operated solenoid valves to turn on the water and deliver a measured dose at the time the owner programs into the controller.
In some locations, there are two pressurized water systems; one for potable water and a second for nutrient-rich irrigation water. The irrigation water receives no chlorination and is unsafe for drinking or bathing. In other locations, the lawn sprinklers use potable water for the lawn and garden.
The system divides the lawn into several sections. At the appropriate time, the controller opens the valve for the first section and the sprinklers operate at the time the operator has set into the controller. Most systems continue through the various zones until they water the entire lawn. The program determines if the system waters the lawn one or more times per day and the days of the week for watering.
Most lawn systems use pop-up irrigation heads. When the solenoid valve activates water to a zone of the lawn, the water pressure forces the sprinkler head out of its storage cavity so it delivers water over the top of the lawn. The gear-driven sprinklers move the stream back and forth to ensure it covers the area. When the valve closes, the water pressure drops and the spray heads drop back into the storage tube. They remain out of the way so landscapers can mow the grass without damaging them.