An irrigation system is a network of pipes, valves, and sprinkler heads buried in your yard. When something goes wrong — a head does not pop up, a zone will not turn on, or water geysers from the lawn — the fix is usually simpler and cheaper than you expect. Most sprinkler repairs require nothing more than a shovel, a few fittings, and an hour of your time.

How to Fix Common Sprinkler System Problems

Broken or Clogged Sprinkler Head

This is the most common sprinkler problem. Heads get hit by mowers, stepped on, or clogged with dirt.

Symptoms: Head does not pop up, sprays erratically, or leaks water constantly.

Fix: Dig around the head to expose the riser fitting. Unscrew the head counterclockwise from the riser. Inspect the filter screen at the base of the head — remove it and rinse it clean.

If the head is cracked or the spring is weak, replace the entire head. Match the type (pop-up, rotor, or fixed spray), the height, and the nozzle pattern. Heads cost $3 to $15 each and screw right onto the existing riser.

Thread the new head onto the riser hand-tight, then snug it a quarter turn with pliers. Wrap the threads with Teflon tape if the connection leaks.

Leaking at the Head

Water pooling around a head while the zone is off indicates a low-head drainage problem or a leak at the fitting.

Low-head drain: The lowest head in a zone drains the water remaining in the pipes after the valve shuts off. Install a check valve adapter under the head to prevent this. Most replacement heads have built-in check valves — look for “SAM” (Seal-A-Matic) models.

Fitting leak: Dig up the connection. If the threaded fitting is cracked, cut it out and install a new one using barb fittings or compression couplers. Teflon tape or pipe dope on all threaded connections prevents leaks.

Broken Pipe

A broken underground pipe causes a flooded zone, low pressure across multiple heads, or a wet spot in the yard that never dries.

Find the break: Turn on the zone and look for water bubbling up or an area of unusually green, soggy grass. Dig carefully to expose the pipe.

Repair: Cut out the damaged section with a PVC pipe cutter or hacksaw. Use a slip-fix coupler (a telescoping repair coupler that slides over both pipe ends) or two standard couplers with a short piece of replacement pipe. Use PVC primer and cement on all joints. Let the cement cure for the time specified on the label before turning the water back on.

For poly pipe (black flexible tubing), use barb fittings and stainless steel clamps instead of glue.

Zone Will Not Turn On

If a zone does not activate, the problem is usually the valve, the wiring, or the controller.

Check the controller: Verify the zone is programmed and the station is not disabled. Try running the zone manually from the controller. If it works manually but not on schedule, the programming needs correcting.

Check the valve: Locate the valve box for that zone (usually a green or black plastic lid in the ground). Open the lid and find the solenoid — the cylindrical part on top of the valve with two wires. Turn the solenoid counterclockwise a quarter turn to manually open the valve. If water flows, the valve works and the problem is electrical.

Check the wiring: Test for voltage at the solenoid wires using a multimeter while running the zone from the controller. You should see 24 to 28 VAC. No voltage means a wiring break between the controller and the valve — trace the wire and look for damage from digging, rodents, or corrosion.

Valve Will Not Shut Off

A valve that stays open after the zone shuts off usually has a torn diaphragm or debris under the diaphragm.

Fix: Turn off the water supply. Remove the screws on the valve bonnet (top). Lift out the diaphragm — a round rubber disc. Inspect it for tears, holes, or hardening. Clean any grit from the diaphragm and the valve seat. Replace the diaphragm if it is damaged — rebuild kits cost $5 to $10 and match by valve brand and model.

Reassemble, turn the water back on, and test.

Low Pressure Across the System

If all zones have low pressure, check the backflow preventer. A partially closed shutoff valve or a failed check valve inside the backflow device can restrict flow. Open all shutoff valves fully. If the backflow preventer is the issue, hire a licensed professional for repair or testing — backflow devices protect your drinking water supply and are regulated in most jurisdictions.

Also check for a partially closed main shutoff valve at the water meter.

Winterizing

In freezing climates, blow out the system with compressed air before the first hard frost. Connect an air compressor to the system’s blowout port and run each zone until only air exits the heads. This prevents pipe and fitting damage from frozen water.

Most sprinkler problems are inexpensive, localized repairs. Keeping spare heads, a roll of Teflon tape, and a few PVC fittings in your workshop means you can fix most issues the same day you spot them.