Irrigation systems can waste significant amounts of water and fail to properly nourish a lawn if sprinkler heads are not correctly aimed. Adjusting a sprinkler head involves correcting the water’s direction and distance to ensure accurate, uniform coverage. This simple maintenance task prevents misplaced watering onto sidewalks or driveways, promoting healthier landscaping while conserving water resources.
Necessary Tools and Initial Preparation
Adjusting sprinkler heads requires only a few specialized tools. For most adjustments, a narrow flathead screwdriver is needed to manipulate the radius control screw. If you have gear-driven rotary sprinklers, you will also need a brand-specific adjustment key, often a small, specialized plastic or metal tool designed to fit the head’s unique keyhole. For spring-loaded pop-up heads, a pull-up tool can be helpful to safely raise the head for easier access to the nozzle.
Preparation begins by briefly running the irrigation zone to identify which heads are misdirected or spraying too far. Observing the active system clearly shows the current spray pattern and highlights areas of overspray or insufficient coverage. It is also important to identify the type of head you are adjusting, distinguishing between rotor heads, which rotate back and forth, and fixed spray heads, which maintain a static fan of water. Rotor heads have more complex adjustment mechanisms for both arc and distance, while fixed heads often only allow for distance reduction or require physically twisting the entire nozzle.
Directing the Spray Arc
The spray arc defines the angular sweep of the water from the sprinkler head, typically ranging up to a full 360-degree circle. For rotor heads, adjustment begins by locating the fixed right stop, which is the non-moving boundary of the rotation. This right stop is set by manually rotating the head clockwise until it stops and aligns with the edge of the area you intend to water. The spray direction is always referenced from this fixed right stop.
To adjust the arc’s width, the specialized adjustment key is inserted into the designated slot on the top of the rotor head, often marked with plus and minus symbols. Turning the key counter-clockwise will increase the arc, moving the left stop further away from the fixed right stop. Conversely, turning the key clockwise will decrease the arc’s angle, tightening the spray pattern. For fixed spray heads, the pattern is usually set by physically gripping the outer edges of the nozzle and twisting the housing to align the arc with the desired watering area.
If the fixed spray head has a variable arc nozzle, a collar or small screw on top allows the arc to be adjusted without replacing the entire nozzle. The arc can be set anywhere from 40 to 360 degrees on many rotor models, offering precise control. After setting the arc, run the system again to confirm the head rotates between the desired boundaries, ensuring the water does not stray onto hardscape surfaces.
Controlling the Water Throw
Controlling the water throw, or radius, determines the distance the water travels from the sprinkler head. This adjustment is managed by a radius set screw, a small screw positioned near the center of the nozzle opening. This screw interrupts the water stream as it exits the nozzle, breaking up the flow to reduce the throw distance.
To shorten the water throw, turn the set screw clockwise using a flathead screwdriver, driving the screw deeper into the stream path. Each turn restricts the flow, reducing the radius by a small increment, often up to about 25% of the nozzle’s maximum rated distance. To increase the throw distance, the screw is turned counter-clockwise to pull it back out of the water stream.
After adjusting the radius, run the sprinkler system to observe the water’s landing point. The goal is to achieve head-to-head coverage, meaning the water from one head reaches the head next to it, which ensures uniform water distribution. If distance reduction is insufficient, the only other option is to replace the existing nozzle with one that has a lower flow rate or a shorter maximum throw distance. It is important to make small, incremental adjustments to the set screw and check coverage frequently to avoid over-tightening the screw, which can strip the plastic threads or completely block the water flow.