How does an impact sprinkler work? A technical guide.

12 08, 2025

Content

1 Water Pressure Starts Things Off:
2 The Water Jet Hits the Arm:
3 The Impact Force Swings the Arm:
4 A Spring Pulls the Arm Back:
5 The Arm "Clicks" Back and Rotates the Sprinkler:
6 The Cycle Repeats:
7 Gradual Rotation Creates Coverage:

Here's how an impact sprinkler works, broken down step-by-step:

Water Pressure Starts Things Off:

When you turn on the water, it flows under pressure into the sprinkler body.
This pressurised water is forced out through a single, relatively small opening called the nozzle. This creates a strong, focused jet of water.

The Water Jet Hits the Arm:

Sticking out in front of the nozzle is a weighted arm (often called the impact arm or hammer).
The powerful jet of water shooting out of the nozzle hits the underside of this arm.

The Impact Force Swings the Arm:

Getting hit by the fast-moving water jet gives the impact arm a sharp knock or "impact."
This force pushes the weighted arm rapidly backwards and upwards, away from the nozzle.

A Spring Pulls the Arm Back:

Attached to the impact arm is a spring.
As soon as the water jet knocks the arm back, this spring stretches.
Once the arm reaches its furthest point, the spring's tension takes over. It pulls the weighted arm back down forcefully towards its starting position.

The Arm "Clicks" Back and Rotates the Sprinkler:

The spring snaps the impact arm back down into the path of the water jet.
As it slams back into place, it makes the familiar "clicking" or "ticking" sound associated with impact sprinklers.
Crucially, when the arm snaps back into the water stream with force, this action gives a tiny nudge to the entire sprinkler body.
Because the sprinkler is mounted on a pivot point, this nudge causes the whole sprinkler head to rotate a very small amount.

The Cycle Repeats:

The water jet immediately hits the arm again, knocking it back.
The spring pulls it back down, causing another "click" and another small rotation.
This continuous cycle – water hits arm, arm flies back, spring pulls it down, arm clicks back and nudges the sprinkler – happens very rapidly.

Gradual Rotation Creates Coverage:

Each time the impact arm snaps back, it rotates the sprinkler head just a tiny bit.
Because this cycle repeats constantly, the sprinkler slowly but steadily rotates in a circle.
As it rotates, the strong jet of water spraying from the nozzle is directed in all directions around the sprinkler over time, watering a large circular area.

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