Adjusting sprinkler heads is fundamental for efficient water use and maintaining a healthy landscape. Improperly set heads cause water waste through overspray onto hard surfaces or uneven watering, leading to dry patches. Fine-tuning your irrigation system ensures water is delivered precisely where needed, benefiting turf health and reducing utility costs. The adjustment method depends entirely on the type of sprinkler head installed.
Understanding Sprinkler Head Categories
Sprinkler heads are categorized into two main groups: fixed spray heads and rotor heads. Fixed spray heads are static, releasing a constant fan-shaped sheet of water to cover a specific area, like a quarter or half-circle. These heads are best suited for smaller turf areas and planting beds, typically throwing water a maximum distance of 15 feet. A small, flathead screwdriver is the primary tool needed for adjusting fixed spray heads.
Rotor heads utilize rotating streams of water to cover a much larger area. This gear-driven type throws water over longer distances, often ranging from 20 to 50 feet or more, making them common for large lawn sections. Rotor heads require a specialized adjustment key, often provided by the manufacturer. This key typically has a plastic end for arc control and a metal hex or flat end for radius control.
Step-by-Step Adjustment for Fixed Spray Heads
Adjusting fixed spray heads involves modifying the radius (distance) and the arc (pattern). The radius is controlled by a small radius reduction screw located on top of the nozzle. Turning this screw clockwise drives it into the water stream, shortening the spray distance. Turning the screw counter-clockwise reduces the obstruction, allowing the water to spray farther.
Fixed spray nozzles are typically designed to have their radius reduced by up to 25 percent of their rated distance. If a greater reduction is required, replace the nozzle with one of a smaller radius to maintain a proper spray pattern. For arc adjustment, many modern heads feature a variable arc nozzle. This nozzle can be twisted by hand or with a special tool to set the desired coverage angle by twisting the outer collar while holding the head steady.
If your fixed head uses a fixed-arc nozzle (e.g., 90-degree or 180-degree), the arc cannot be changed. The only adjustment is correcting the direction of the spray pattern. Accomplish this by manually twisting the entire pop-up riser assembly within the sprinkler body. This ratcheting movement allows fine-tuning the coverage direction without digging up the head.
Step-by-Step Adjustment for Rotor Heads
Rotor heads require precise calibration of the fixed-stop position and the arc of rotation. Locate the head’s fixed stop, which is the point where the head reverses direction, usually the right-hand side of the pattern. This fixed stop must be aligned with the boundary of the area you intend to water. Align the stop by rotating the entire pop-up riser assembly until the head points in the correct starting direction.
Once the fixed-stop is positioned, set the arc of rotation using the specialized adjustment key in the designated arc port, often marked with plus and minus symbols. Turning the key clockwise increases the arc, widening the angle of rotation. Turning it counter-clockwise decreases the arc. Most rotor heads can be adjusted from a small partial circle (as low as 40 degrees) up to a full 360-degree circle.
The radius of a rotor head is controlled by inserting the hex or flat end of the adjustment key into the radius reduction screw, located near the center of the nozzle. Turning this screw clockwise drives it into the water stream, shortening the radius by causing the stream to break up. Be cautious not to turn this screw too many times. Over-tightening can cause the screw to fall out or damage internal nozzle components.
Verifying Coverage and Final Checks
After making adjustments, run the zone and observe the spray pattern to verify coverage. The goal is to achieve “head-to-head” coverage, meaning water from one head should reach the adjacent sprinkler head. This overlap is necessary because water distribution is naturally uneven. Overlapping the patterns ensures uniform water application across the entire area.
A second important check is looking for overspray, which is water landing on impervious surfaces like driveways or sidewalks. Overspray wastes water and can cause premature wear on structures. If detected, slightly reduce the radius or fine-tune the arc to pull the spray back within the turf boundaries. Finally, ensure all pop-up heads fully retract below the turf surface once the irrigation cycle is complete. Failure to retract indicates a problem with the spring mechanism or debris, potentially leading to damage from equipment.