A sprinkler system might seem complicated, but it is pretty simple at its core. Five essential components comprise an in-ground automatic sprinkler system: a controller, pipes, valves, sprinkler heads, and a backflow preventer.

Understanding the roles of these fundamental components is essential for installing and maintaining your system. Once you know what each piece does, you’ll be better equipped to troubleshoot problems and keep your system in good working order.

Essential Components of an Automatic Sprinkler System

While there are many different working pieces in an in-ground automatic sprinkler system, everything boils down to five basic components. These parts are the nuts and bolts of the system and are necessary for it to work.

• Controller or timer: acting as the brains behind the operation by managing the timing and duration of irrigation cycles
• Pipes or tubing: serving as the network of conduits that transport water throughout the system
• Valves: regulating the flow of water to individual sections
• Sprinkler heads: responsible for dispensing water in a controlled manner across designated zones
• Backflow preventer: safeguarding the potable water supply by preventing contamination

How Water Moves Through a Sprinkler System

Water Flows from the Source Into the System

Your home’s water source, whether a well or local municipal water, brings water to your system’s mainline. The mainline branches off the source—usually at a spigot or by tapping into the service line—and carries water into your irrigation system.

PVC or polyethylene pipe carries the water to a backflow preventer.

The Job of a Backflow Preventer

A backflow preventer does precisely what its name suggests. Its purpose is to prevent water from flowing backward into your home’s drinking water once it's inside your sprinkler system, preventing contamination.

In many systems, the backflow preventer is also where you can shut off the water to your sprinklers.

The water flows through your pipes to the valves from the backflow preventer.

A Controller Tells The Valve To Open

The sprinkler controller is the brain of an irrigation system. It tells the valves that control a group of sprinkler heads (i.e., a zone or station) when to open or close.

When the timer reaches the programmed start time, it sends an electrical signal to the valve, telling it to open. When the end of the programmed runtime is reached, the timer sends another signal to the valve, this time telling it to close.

Water Flows Through the Piping and Tubing

Once opened, the valve allows water to flow through the pipes into a zone of sprinkler heads. The type of pipe depends on several factors, primarily your climate, but PVC and polyethylene (sometimes called funny pipe) are the two most commonly used.

• The standard 1-inch PVC pipe used for sprinkler systems can withstand water pressure of 200 psi. It is rigid, with thicker walls, which is how it can handle the higher pressure.
• 1” Polyethylene, or poly pipe, is more flexible because of its thinner walls. It can only withstand water pressure of 100 psi.

Both are entirely adequate for in-ground sprinkler systems. However, polypipe is better suited for colder climates as its flexibility allows it to tolerate freezing weather.

Pop-Up Sprinklers Are Activated

Pop-up sprinklers are loved because they hide neatly underground until it’s time for them to work. When a zone is activated by the controller and the valve is opened, water flows through the pipe to the sprinkler heads. The resulting water pressure from the flow pushes the sprinkler heads out of the ground. Hence, they “pop up.”

Most pop-up sprinkles rise three or four inches above the ground, positioning them slightly above the grass. They can then effectively water without the lawn obstructing the spray, yet they don’t throw the water overly high, increasing the chance of evaporation.

Standard pop-up sprinklers include fixed spray, gear-drive rotors, and multiple stream heads.

• Fixed spray heads are stationary. They emit a tight fan of water in a constant direction and distance. They typically spray 45 to 360° up to 10 or 12 feet.
• Gear-drive rotors have internal gears that spin the heads, thus allowing them to spray much further than fixed heads. They typically spray a single stream of water up to 35 feet.
• Multiple spray sprinkler heads also rotate, distributing multiple thin streams of water. They aren’t as powerful as gear-drive rotors, typically spraying up to 15 feet.

When the controller tells the valve to close, water stops flowing through the pipes, the water pressure inside the zone drops, and the sprinkler heads fall back into the ground.

The process repeats for every zone in your sprinkler system.