Adjusting lawn sprinkler heads is a simple maintenance task that greatly influences the health of your turf and the efficiency of your irrigation system. Properly aimed and calibrated sprinklers ensure water reaches the grass roots, promoting deep growth while minimizing runoff and waste. Precise adjustment prevents overspray onto non-landscape areas, such as sidewalks or driveways, which conserves water and prevents property damage. Fine-tuning each head allows for uniform coverage, preventing dry patches and over-watered spots that can encourage disease.
Essential Tools and Understanding Sprinkler Head Types
Before beginning adjustments, gather a small flathead screwdriver and a specialized plastic adjustment tool, often called a sprinkler key. The adjustment method depends entirely on the type of head installed. Residential systems primarily use two types: Spray Heads and Rotor Heads.
Spray Heads are designed for smaller lawn areas, typically covering distances less than 15 feet, applying water in a fixed, non-moving fan pattern.
Rotor Heads are gear-driven, emitting streams of water that rotate back and forth over large areas, often covering 20 to 50 feet or more. The techniques for radius and arc control differ significantly between these two head types.
Adjusting the Throw Distance (Radius Control)
Controlling the distance the water travels, known as the radius, is the first step toward achieving uniform coverage. For Spray Heads, the radius is adjusted using a reduction screw located in the center of the nozzle. Turning this screw clockwise drives it into the water stream, reducing the throw distance. Turning it counter-clockwise increases the distance up to the nozzle’s maximum rating.
Turning the screw in too far causes the water stream to split and become mistier, which reduces efficiency and makes the water susceptible to wind drift and evaporation. If a large reduction is necessary, it is better to replace the nozzle with a lower-radius option instead of over-tightening the screw.
Rotor Heads also feature a radius reduction screw protruding into the path of the water stream. Turning this screw clockwise shortens the spray distance by deflecting the water, allowing for a reduction of up to 25% of the head’s maximum throw.
If the desired distance is still not met, the head’s nozzle must be physically exchanged. This requires lifting the pop-up stem and inserting a new nozzle with a lower flow rate.
Adjusting the Spray Pattern (Arc Control)
Adjusting the arc defines the angle or degree of rotation the sprinkler covers, ensuring water is applied only where the grass is growing. Many Spray Heads use Variable Arc Nozzles (VANs) that allow the user to twist the outer ring of the nozzle by hand to expand or contract the spray pattern from a narrow angle to a full 360-degree circle. For fixed-arc spray heads, the entire pop-up riser assembly must be physically rotated inside its housing to align the fixed spray pattern with the desired area.
For Rotor Heads, arc adjustment involves setting the right and left stops of the rotation. The right side is the fixed stop, set by rotating the head’s turret by hand until it aligns with the edge of the area to be watered.
The left stop, which determines the arc width, is adjusted using the specialized plastic key inserted into a socket on the head’s top. Turning the key clockwise increases the arc angle, expanding coverage from the fixed right stop, while turning it counter-clockwise decreases the arc.
Fine-Tuning and Troubleshooting Common Sprinkler Problems
Once initial adjustments are complete, run the system through a full cycle to observe the coverage pattern. A proper setup utilizes “head-to-head” coverage, meaning the spray from one head should reach the adjacent head to ensure there are no dry pockets. Observing the water stream allows you to make micro-adjustments, ensuring the spray remains low to the ground and is not misting or carried away by the wind.
If a sprinkler head is not popping up fully or the throw distance is short, the issue is often low pressure or a clogged nozzle. Low system pressure results in a weak stream, sometimes requiring the installation of pressure-regulating heads.
Clogged nozzles disrupt the spray pattern and can be remedied by removing the nozzle and cleaning out debris or mineral buildup with a small brush before reinstallation. Misaligned heads require only a slight twist to redirect the spray from a sidewalk back onto the lawn area.