Properly adjusting an irrigation sprinkler system influences landscape health and water conservation. When sprinkler heads are misaligned or incorrectly calibrated, they waste water by spraying pavement or overwatering zones, leading to runoff and higher utility bills. Conversely, poor adjustment can leave dry spots, damaging the lawn or garden due to insufficient hydration. Fine-tuning the system ensures that water is delivered uniformly and efficiently where it is needed most.
Essential Preparation and Tools
The initial step before making any adjustments involves safety and system isolation. Shut off the main water supply to the irrigation zone you plan to work on. This prevents unexpected water activation while the head is exposed or being manipulated. Once the water is off, gather the necessary tools.
The most common tool required for both rotor and spray head adjustments is a narrow flat-head screwdriver. This tool manipulates the radius adjustment screw found on top of most nozzles. For gear-driven or rotary heads, a specialized rotor adjustment tool or key is often necessary to set the arc and internal mechanisms. For pop-up heads that have sunk into the turf, a small shovel or trowel will be needed for excavation.
Understanding Your Sprinkler Head Type
Adjusting an irrigation system first requires identifying the type of sprinkler head being used, as adjustment methods vary significantly. The two primary types found in residential settings are spray heads and rotor heads. Spray heads are typically used for smaller areas, such as narrow lawn strips or flower beds, and emit a consistent, fan-shaped spray pattern.
Rotor heads are designed for medium to large-sized lawn areas and distribute water by slowly rotating in a circular or semi-circular pattern. They apply water at a much slower rate, which is beneficial for sloped or clay-heavy soils. Rotor heads can cover distances from 30 feet up to 90 feet in some commercial models.
Adjusting the Spray Distance
Modifying the throw distance, or radius, of a sprinkler head is generally accomplished using a flat-head screwdriver on the flow restrictor screw located on the nozzle. This screw, sometimes called the diffuser screw, extends into the path of the water stream to disrupt the flow. Turning the screw clockwise drives it further into the stream, shortening the distance the water travels by breaking up the trajectory. Conversely, turning the screw counter-clockwise retracts it, allowing the stream to be more cohesive and increasing the spray distance.
This principle applies to both fixed spray heads and rotor heads. The maximum adjustment is usually limited to a reduction of about 25 to 35 percent before the spray pattern becomes distorted. If a greater distance change is needed, the entire nozzle component must be replaced.
Adjusting the Spray Arc
The spray arc refers to the width of the pattern, controlling the area being covered, such as a quarter-circle or a full circle. For adjustable rotor heads, the arc is set by first establishing a fixed stop point and then adjusting the rotational limit using a specialized tool. The process involves rotating the turret to its left stop, which is the starting position, and then holding the turret at the right stop to make the adjustment. A rotor key is inserted into the designated adjustment socket; turning it clockwise increases the arc, while turning it counter-clockwise decreases the arc.
For fixed spray heads, the arc is either non-adjustable and set by the specific nozzle installed, or it can be a variable arc nozzle that is physically rotated by hand. In many fixed spray systems, if the arc needs to be changed, the entire nozzle must be replaced with one designed for the new pattern.
Aligning and Setting Head Height
Physical alignment adjustments ensure the sprinkler head is level with the ground surface and correctly pointed in the desired direction. A tilted head causes uneven water distribution, resulting in overwatering on one side and dry spots on the other. Straightening a crooked head typically involves digging carefully around the base to expose the connection and then repositioning the riser vertically before backfilling the soil. If the head has sunk over time, it must be raised back to grade to prevent damage from lawn mowers or blockage by grass. This requires excavating the soil and adding a riser extension until the top of the head is level with the surrounding turf.