How to Adjust Sprinkler Heads (And When to Call a Pro)

A sprinkler head spraying the sidewalk or missing half the yard is annoying and wasteful. The good news: most adjustments take five minutes and no special skills. Here's how to do it.

Tools You'll Need

• A flat-head screwdriver (small, like an eyeglass screwdriver works great)
• A rotor adjustment key (a small plastic tool that comes with most Hunter and Rain Bird rotors. If you don't have one, they're a couple bucks at any hardware store or irrigation supply house.)
• That's it.

Adjusting Pop-Up Spray Heads

These are the shorter heads (usually 4-6 inches tall when popped up) that spray a fixed fan pattern. They're common in smaller zones, along walkways, and in tight areas. Most brands (Rain Bird, Hunter, K-Rain) adjust the same way.

To adjust the spray pattern (arc):

1. Turn on the zone so the head pops up
2. Look at the top of the nozzle. You'll see a tiny screw or slot on top
3. Use your flat-head screwdriver to turn it
4. Turning clockwise reduces the spray distance (pulls it in closer)
5. Turning counter-clockwise increases the spray distance (pushes it out farther)

To change the spray angle (direction):

1. Grab the top of the nozzle (the colored part) while it's popped up
2. Twist it to rotate the spray pattern left or right
3. On adjustable-arc nozzles, you can also widen or narrow the arc by twisting the adjustment ring

To fix a head that's spraying off-target:

Sometimes the whole head body has rotated in the ground. Grab the nozzle when the zone is on and gently twist the entire riser to point it where it needs to go. If it keeps spinning, the head body needs to be dug up and reset.

Adjusting Rotor Heads

Rotors are the bigger heads that rotate back and forth, throwing water 20-45 feet. They cover large lawn areas. Adjusting them is a little different.

Setting the left stop (fixed edge):

1. Turn on the zone so the rotor pops up
2. Let it rotate all the way to one side. That side is the left stop.
3. To change it, grab the nozzle turret and twist it. The left stop moves with the turret.

Setting the arc (how far it sweeps):

1. Find the arc adjustment screw on top of the rotor. It has a +/- symbol.
2. Insert your rotor adjustment key
3. Turning the + direction widens the arc
4. Turning the - direction narrows the arc
5. Most rotors adjust from about 40 degrees to 360 degrees

Adjusting throw distance:

1. There's a small screw on top of the nozzle (separate from the arc screw)
2. Turn it clockwise with a flat-head to reduce the distance
3. Turn it counter-clockwise to increase it
4. This works by deflecting some water downward, so turning it in too far will create a wet spot near the head

Fixing a Head That Won't Pop Up

If a head isn't popping up at all, check these things before replacing it:

Debris around the stem. Dirt, grass clippings, and mud can pack around the riser and prevent it from popping up. Dig around the head, clean off the stem, and pop it up by hand a few times to free it up.

Low pressure. If other heads on the same zone are weak too, you might have a pressure issue. Check the valve for that zone. It might not be opening fully.

Cracked or broken head. If the head pops up but water sprays from the body instead of the nozzle, the body is cracked. Pull it out and replace it. Pop-up spray heads cost $3-$8 at any hardware store and thread right onto the existing fitting.

Mower damage. Heads that sit too high get clipped by mower blades constantly. If you're replacing the same head over and over, it probably needs to be lowered.

When to Call a Pro

DIY adjustments handle about 80% of sprinkler head issues. But some problems go deeper than the head itself. Call a professional when you see:

• A valve that won't turn on or off. That's an electrical or valve issue, not a head issue. It involves wiring back to the controller or a stuck/broken valve underground.
• Underground leaks. If a zone drops pressure or you see soggy spots between heads when the system is off, there's a pipe leak underground. That requires digging and pipe repair.
• Heads that break repeatedly in the same spot. If you keep replacing a head and it keeps cracking, the fitting underground might be damaged, or there's a pressure surge on that zone.
• Uneven coverage you can't fix with adjustments. Sometimes the original design just has bad head spacing. Fixing that means adding heads or relocating existing ones, which involves trenching and new pipe.
• Any wiring issues. If zones won't turn on from the controller, don't start cutting wires. Irrigation wiring is low voltage but still needs proper diagnosis with a multimeter.

Trailhead Lawn & Irrigation handles sprinkler repairs and adjustments across Erie, Longmont, Louisville, Lafayette, and surrounding areas. If you've tried the DIY route and things still aren't right, give us a call. We'll get your coverage dialed in.