Signs your irrigation system is leaking
Common clues include:
- A water bill that rises without a clear reason.
- Soggy or muddy ground, or pooling water, especially when the system is off.
- Sprinklers that spray weakly, unevenly or not at all.
- A fountain of water from a broken head.
- Unusually green or fast-growing grass in a strip or patch, or dry spots elsewhere because of lost pressure.
- Hissing sounds or water in valve boxes.
Is it your irrigation system or your household plumbing?
A wet yard can come from rain, poor drainage, a high water table, irrigation, or a leak in the main water line. A water meter can help sort this out:
- Turn off all water use inside and outside the house.
- Check the meter. A spinning dial or low-flow indicator, or a flow reading above zero on a digital meter, means water is moving somewhere.
- Shut off the irrigation system’s supply valve or backflow preventer, then check the meter again.
- If the meter stops, the leak is likely in the irrigation system. If it keeps moving, the leak is somewhere else in the plumbing.
A leak in the main supply line to the house is a plumbing problem rather than a sprinkler problem. If you suspect that, a plumber or leak detection company is the right call; see water main leak to house for the signs.
Find the leak
Check the valve boxes
Open each valve box lid. Standing water or very wet soil around the valves suggests a leaking valve or fitting. Dry soil points elsewhere.
Run each zone
Turn the controller on and run one zone at a time. Watch for:
- A head that is cracked, tilted or spraying water out of the wrong place.
- Weak or inconsistent spray, which can suggest a leak below ground.
- Water bubbling up or pooling along the pipe line.
Mark problem spots with landscape flags so you can find them again once the water is off.
Look for soggy or unusually green areas
If heads and valves look fine, the leak is probably in the buried pipe. Wet ground along the line between heads is a typical sign. Pipe leaks can be hard to find, and digging in several places may be needed. Water pooling near the house can also seep into a basement; see water leaking through a foundation or basement.
Can irrigation leak when it is off?
Yes. A zone valve that does not close fully because of debris, a worn diaphragm or a failing solenoid can let water trickle through. Low-lying heads can also drain after a cycle, causing wet ground near them. A pressurized line that cracks or a fitting that fails will leak whether the controller is running or not. The meter test above helps tell whether water is leaking while the system is off.
Before you dig: shut off water and locate utilities
- Turn off the controller so zones do not start while you work.
- Shut off the irrigation supply valve.
- Call your local utility locating service before any digging. In the United States, dial 811. Buried gas, electric and communication lines can be dangerous or costly to hit, and irrigation lines are often shallow but near other utilities.
- Disconnect power to the controller or valve wires if you plan to work on a valve, and keep wiring away from water.
- If you smell gas or find damaged utility lines, leave the area and call the utility company or emergency services.
Fixing common leaks
Sprinkler heads
Cracked or broken heads are among the easiest repairs. Dig carefully around the head, remove the old head, check the riser or fitting, and screw on a replacement of the same type. Flush the line briefly to clear dirt before installing the new head.
Zone valves
Valve leaks are often caused by a damaged diaphragm, debris, or a failing solenoid. With the water off, remove the valve cover or bonnet, inspect and clean the diaphragm, and replace it or the solenoid if damaged. Take photos or the old part to the store to match it. If the valve body is cracked or fittings are damaged, replace the valve.
Pipe and fittings
For a cracked pipe, expose the pipe, cut out the damaged section and install a repair coupling or replace the section with matching pipe, size and type (commonly PVC or polyethylene). Make sure the new connection matches the existing material and follow the fitting manufacturer’s instructions. Pipe repair near the house, the main shut-off, or near the backflow preventer is better left to a professional.
Drip lines
Drip tubing is often repaired with couplings or plugs. Replace cracked emitters and fittings. Dirt in lines can clog and cause pressure problems, so flush the line after repairs. The “30/30” rule sometimes mentioned for drip systems is not something we can confirm as a standard, so follow your system’s manufacturer instructions for run times.
How long do sprinkler valves last?
Lifespans vary with water quality, pressure, installation and use. Many valves last years, and some last a decade or more, but diaphragms and solenoids can wear out sooner. If a valve repeatedly leaks or sticks, replacement is often more practical than repeated repairs.
How much does it cost to fix an irrigation leak?
Costs vary with the type of leak and your region. A replacement head or diaphragm is usually inexpensive, while locating and repairing an underground pipe leak or replacing valves costs more, especially if a contractor is hired. A written quote is the best way to get a reliable figure.
When to call a professional
Contact a licensed irrigation contractor or plumber if:
- You cannot locate the leak.
- The meter shows flow even with the irrigation shut off.
- The leak is on the main line, near the water meter, or at the backflow preventer. Backflow preventers protect drinking water, and some areas require licensed professionals for work on them.
- You must dig near buried utilities or tree roots.
- Wiring or controller problems are involved.
If you also have a pool, water loss there can look like an irrigation or plumbing problem. See our guide on how to fix a crack in a pool to learn about confirming pool leaks.