An irrigation controller can be located outside or inside, depending on the type of controller. A wire runs from the controller along the main irrigation line to the water valves. Wires from the irrigation controller are individually connected to each of the water valves so that the valves can be controlled independently of each other. A white wire, known as the common wire, is connected to all of the water valves for easier control. The controller is programmed with several schedules that apply to individual water valves and their zones. When the controller activates a valve, the valve opens and the water rushes to the sprinklers.
Several sprinklers are connected to one water valve, and an irrigation system can contain more than one water valve. For example, a home might have two water valves in an irrigation system: one to water the backyard and one to water the front yard. These sections of the yard might not receive the same amount of sun exposure, thus they each have different watering needs. Water valves are connected together and receive water from the irrigation water line, which is usually connected to the main water line. The connected valves are underground inside of a box called the valve manifold box. There can be more than one box, depending on how many valves there are, and they usually have green lids.
Sprinklers come in many forms to suit the needs of the lawn. A sprinkler can be stationary above ground or be installed underground. Some sprinklers spray only in one direction while others contain different rotation ranges that sometimes reach 360 degrees. The sprinklers are all connected to a water valve. The sprinklers pop up from their hidden underground position to water the lawn when the irrigation controller "tells" its connected water valve to open. The sprinklers are all connected to the same water valve line by piping.
Many pipe materials exist for irrigation systems with different local codes. Some areas require polyvinyl chloride (PVC) pipes while others require copper or galvanized pipes. Pipes are connected to fittings, which are screwed or slipped into the valves and sprinklers. Sealing pipe connections and fittings properly with Teflon tape, primer or glue is necessary lest you have a leak on your hands. Before you move forward with major planning or purchases, confer with your local codes.