Adjusting an irrigation system is essential for maintaining a healthy landscape and managing water responsibly. When a sprinkler head is misaligned, it directs water onto hard surfaces like sidewalks, driveways, or fences, resulting in water waste and potential damage. Proper directional adjustment ensures water is applied directly to the plant root zones, promoting robust growth and maximizing irrigation efficiency.
Identifying Your Sprinkler Head Type
The method for adjusting a sprinkler’s direction and coverage depends on the specific type of head installed. Homeowners typically encounter two primary types: the rotor head and the fixed spray head.
Rotor sprinkler heads emit a single stream of water that rotates back and forth or in a full circle. Used for larger areas (15 to 50 feet), these heads utilize a gear-drive system. Adjusting the arc and direction requires a specialized tool or a small flathead screwdriver.
Fixed spray heads are simpler devices that emit a continuous, fan-shaped pattern, covering smaller areas (5 to 15 feet). They spray a fixed arc, such as a 90-degree quarter circle. Since they lack internal moving parts for directional control, adjustment involves manually repositioning the head or replacing the nozzle to change the pattern.
Adjusting Rotor Sprinkler Coverage and Direction
Adjusting a rotor head requires setting two parameters: the fixed starting point (left stop) and the rotational distance (arc). First, establish the left stop, which is where the spray begins its movement. This is done by manually turning the nozzle turret all the way right until it stops, then turning it back to the desired starting position.
The entire sprinkler body may need to be physically rotated in the ground to align the left stop with the edge of the watering area. Once the left stop is set, the arc adjustment is made using a specialized tool or a narrow flathead screwdriver inserted into the adjustment slot on top of the head.
The adjustment slot is usually marked with plus (+) and minus (-) signs. Turning the tool clockwise increases the arc, widening the coverage angle from the fixed left stop. Turning the tool counter-clockwise decreases the arc. Rotor heads can typically be adjusted from a 40-degree pattern up to a full 360-degree circle.
It is helpful to make these adjustments while the water is running to observe the new spray pattern in real-time. A ratcheting sound during adjustment indicates that the maximum or minimum arc limit has been reached, which prevents internal gear damage.
Adjusting Fixed Spray Nozzles
Fixed spray nozzles require a different approach for directional and coverage changes than rotor heads. Directional alignment is achieved by manually grasping the sprinkler body and turning it. This adjustment must be done carefully to avoid breaking the connection to the underground plumbing.
To aim the pattern, you may need to dig soil around the base to grip the body and rotate the entire assembly. This action changes the orientation of the nozzle’s fixed spray pattern.
Changing the coverage arc, such as moving from a 90-degree quarter circle to a 180-degree half circle, cannot be done with a simple screw adjustment. Most fixed nozzles spray a predetermined arc, meaning a new nozzle must be installed to change the pattern. The process involves unscrewing the existing nozzle and threading a new one with the desired arc into place.
Some modern fixed spray nozzles have variable arc capability, allowing adjustment without replacement. These nozzles feature a small screw or tab on top. Using a flathead screwdriver, you can turn this screw to expand or contract the physical opening, setting the exact arc angle required.
Controlling the Throw Distance (Radius)
Once the direction and arc are set, the final step is controlling the distance, or radius, of the water throw. This adjustment is universal for both rotor and fixed spray heads and is accomplished using a radius reduction screw. This small metal screw is located on top of the nozzle, positioned to intersect the stream of water.
Turning the screw clockwise drives it further into the stream, acting as a diffuser pin that breaks up the water flow. This interruption shortens the distance the water travels and creates a softer spray pattern. Reducing the radius prevents overspray onto adjacent pathways, fences, or buildings, aiding in water conservation.
Most sprinkler heads allow the throw distance to be reduced by approximately 25% using this screw. If a greater reduction is necessary, the nozzle must be replaced with one that has a lower flow rate. Avoid turning the radius screw too far clockwise, as this can atomize the water, creating a fine mist susceptible to wind drift and evaporation.