Replace the head by turning off the water, unscrewing the old one by hand or with a wrench, and screwing in the new one hand-tight
Most irrigation heads unscrew like a light bulb. Turn off the water at the valve or timer, grip the head near its base, and turn counterclockwise. If it will not budge, use an adjustable wrench on the fitting below ground where the head connects to the riser pipe — do not grip the spray arm itself, which will crack. Once loose, unscrew by hand the rest of the way. Screw the new head on by hand until snug, then stop. Hand-tight is the right tightness; over-tightening cracks the plastic fitting or the new head.
The whole job takes five to ten minutes once you have the new head in hand. You do not need to dig up the riser or drain the line. If water leaks from the connection after you turn the system back on, turn it off again, unscrew the head a quarter turn, and try once more. Leaks at the connection almost always mean the head was cross-threaded — the threads did not line up when you started screwing.
Key Takeaways
- Turn off the water supply before you start, either at the valve feeding that zone or at the main timer.
- Grip the head near its base and turn counterclockwise; if it will not move, use a wrench on the fitting below ground, not on the spray arm.
- Screw the new head on by hand until snug, then stop — over-tightening breaks plastic fittings.
- If water leaks from the connection after you turn the water back on, the threads may be cross-threaded; unscrew and try again.
- Bring the old head to the store so you can match the thread size and spray pattern of the replacement.
What you need before you start
Bring the old head with you to the store or take a photo of the base where it screws on. Irrigation heads come in different thread sizes — the most common are half-inch and three-quarter-inch — and you need the right one or it will not screw on. The photo should show the fitting clearly so the store staff can see the size.
You also need to know what spray pattern you want: full circle, half circle, quarter circle, or adjustable. Most yards use a mix. If you are replacing a head that broke or clogged, buy the same pattern unless you have a reason to change it. An adjustable head costs a few dollars more but lets you dial in the exact arc later without buying a new head.
Bring an adjustable wrench if the old head is stuck. You probably do not need it, but it takes thirty seconds to grab and saves a trip back to the garage if the head will not turn by hand.
Step-by-step: removing the old head
Turn off the water. Find the valve or timer that controls the zone where the broken head is. If you have a smart controller, turn off that zone. If you have a manual valve, turn the handle perpendicular to the pipe. If you have a battery timer on the valve itself, flip the switch to off. Wait ten seconds for the line to depressurize.
Walk to the head and grip it low, just above where it screws into the riser. Turn counterclockwise slowly. If it turns easily, keep going until it comes free. If it does not move after a quarter turn of pressure, stop and get the wrench.
Fit the adjustable wrench onto the fitting below ground — the part the head screws onto. Hold the wrench steady with one hand and turn the head counterclockwise with the other. Once it loosens, remove the wrench and finish unscrewing by hand. Do not force it; if it is stuck, soak the connection with penetrating oil and wait an hour, then try again.
Step-by-step: installing the new head
Look at the threads on the new head and the fitting on the riser. The threads should look clean and dry. If the fitting is caked with mineral deposits or dirt, wipe it with a dry cloth. Do not use water or oil.
Start the new head by hand, turning clockwise slowly. You should feel the threads catch and the head begin to seat. If you feel grinding or resistance, stop when ready, back out, and look at the threads again. Grinding means they are cross-threaded. Start over and go slower.
Once the head is seated and the spray arm is pointing the direction you want, tighten by hand until snug. You should not be able to turn it further without real effort. Stop there. If you use a wrench to tighten it, you will crack something.
Adjusting the spray pattern after installation
Most fixed heads — full circle, half circle, quarter circle — do not adjust. The pattern is set. If you bought an adjustable head, you can dial in the arc now or later. Look for a small screw or dial on top of the head. Turning it clockwise usually narrows the spray; turning it counterclockwise widens it. The adjustment range is usually 25 to 360 degrees, depending on the model.
Turn the water back on and watch the spray. If it is hitting a wall, driveway, or your neighbor's fence, turn off the water, adjust the dial, and try again. Most adjustable heads let you change the pattern without tools, so you can dial it in by trial and error in a few minutes.
Troubleshooting leaks and weak spray
If water sprays from the connection where the head screws on, turn off the water when ready. Unscrew the head a quarter turn and try again. This usually fixes a cross-threaded connection. If it still leaks, unscrew completely, look at the threads on both the head and the fitting, and make sure neither is cracked or stripped. If the threads look fine, explore a thin wrap of plumber's tape to the male threads on the fitting, then screw the head back on.
If the head sprays weakly or not at all, the nozzle may be clogged. Most heads have a removable nozzle on top. Unscrew it by hand and hold it up to the light. If you see sediment or mineral buildup, soak it in white vinegar for an hour, then rinse and reinstall. If the nozzle is clear, the clog is deeper in the line and you may need to call a technician.
When to replace the whole riser instead of just the head
If the fitting the head screws onto is cracked, leaking, or stripped, replacing just the head will not fix it. You will need to replace the riser — the pipe that sticks up from the ground. This is a bigger job that usually requires digging and may need a professional, depending on how deep the riser is buried and whether it is glued or threaded to the main line below.
Signs the riser itself is the problem: water sprays from the base of the riser even when the head is off, the fitting spins freely without tightening, or you see cracks in the plastic riser above ground. If you see any of these, turn off the water and take a photo to show a technician or the store staff. They can tell you whether you can fix it yourself or need help.
Frequently Asked Questions
Can I replace the head without turning off the water?
You can, but you will get soaked. Water will spray out of the riser as soon as you unscrew the head. Turning off the water takes thirty seconds and keeps you dry. If you cannot find the valve, turn off the main water supply to the house instead.
What if the old head is stuck and will not turn?
Use a wrench on the fitting below ground, not on the spray arm. If it still will not budge, spray penetrating oil around the connection, wait an hour, and try again. If it is still stuck after that, the fitting may be glued or corroded; you may need a professional to remove it without breaking the riser.
Do I need plumber's tape on the threads?
No, not usually. Irrigation heads screw on dry. Use plumber's tape only if water leaks from the connection after you have tried unscrewing and rescrewing the head. Tape helps seal a connection that is slightly cross-threaded or has minor thread damage.
How do I know what size head to buy?
Bring the old head to the store or take a clear photo of the base where it screws on. The store staff can match the thread size. If you cannot do either, the most common size is half-inch, but do not guess — buying the wrong size wastes money and time.
Can I use a head with a different spray pattern than the old one?
Yes, as long as the thread size matches. You can replace a full-circle head with a quarter-circle head, or vice versa. Just make sure the new pattern covers the area you want to water and does not spray onto pavement or your neighbor's property.