Watering your lawn and garden efficiently requires sprinkler heads to direct water precisely where it is needed. Proper adjustment ensures uniform water coverage across the landscape, which is the foundation of a healthy lawn. Fine-tuning the direction and spray distance of each head also conserves water by eliminating runoff onto sidewalks, driveways, and other hardscapes. This guide focuses on adjusting the two most common types of residential sprinkler systems.
Identifying Sprinkler Head Types
Residential irrigation systems primarily use two distinct types of sprinkler heads, and the adjustment method depends entirely on the type. The first is the fixed spray head, a smaller unit that pops up and releases a fan-shaped spray of water instantly over a fixed area. These heads are used for smaller, tightly-shaped zones and water at a high rate, with a maximum spray distance usually under 18 feet.
The second common type is the rotor head, designed for medium to large lawn areas. Rotor heads emit single or multiple streams of water that rotate back and forth across an arc. This rotational movement allows them to cover a greater distance, often ranging from 15 to 50 feet. They apply water more slowly than spray heads, which reduces the risk of runoff.
Adjusting Fixed Spray Heads
Adjusting a fixed spray head involves manually repositioning the spray pattern and controlling the distance. To set the direction, grip the stem of the pop-up head and turn the entire nozzle assembly to orient the spray toward the desired area. You may need to firmly hold the head to overcome the internal friction and ensure the spray begins at the correct starting point.
The distance, or radius, of the water throw is controlled by a small flat-head screw located on top of the nozzle. Turning this screw clockwise drives it further into the stream of water, acting as a flow restrictor and reducing the spray distance. Conversely, turning the screw counter-clockwise moves it out of the water path, allowing the head to spray its full intended radius. Make minor adjustments with the system running to accurately observe the changes in the spray pattern.
Setting the Arc and Radius on Rotor Heads
Rotor heads require a specialized approach to set both the rotational arc and the throw radius, often utilizing a small plastic key or flat-head screwdriver. The first step is determining the “left stop,” which is the fixed boundary where the rotation begins. On most modern rotors, reposition this left stop by rotating the nozzle turret manually until it aligns with the desired starting point of the spray.
The arc, which is the total span of the rotation, is adjusted using an access slot, usually marked with a plus (+) and minus (-) sign on the top of the head. Inserting the adjustment tool and turning it clockwise increases the arc, extending the rotation towards the right stop. Turning the tool counter-clockwise decreases the arc, narrowing the spray pattern. Each full turn of the tool often corresponds to a specific change in the arc, and you will hear a ratcheting sound when the minimum or maximum arc is reached.
To control the radius, or distance the water travels, a separate radius adjustment screw is usually located near the nozzle opening. Turning this screw clockwise inserts a pin into the water stream, causing the water to deflect and reducing the throw distance. Most rotors allow the radius to be reduced by up to 25% of the nozzle’s maximum rating. Avoid turning this screw too far clockwise, as excessive restriction can interfere with the nozzle’s stream integrity or cause the screw to become lost.
Troubleshooting Common Adjustment Issues
After making adjustments, several issues can prevent the sprinkler from operating as intended. If a rotor head does not hold the set arc and slips out of position, the internal gears or clutch mechanism may not be fully locking. This can be corrected by ensuring the entire head assembly is firmly seated and not loose in the ground casing.
A common problem with fixed spray heads is the radius adjustment screw being stripped or ineffective at reducing the spray. This means the screw threads are damaged or the internal components are worn, requiring the nozzle itself to be replaced to regain control over the spray distance. If a pop-up head fails to fully extend above the grass line, it may be due to dirt or debris accumulating around the riser seal or within the body of the head. This accumulation increases friction and prevents the head from lifting completely. Cleaning the area around the base and checking for obstructions can restore the proper pop-up height.