Irrigation leaks are a common issue for homeowners, signaling a serious problem. A compromised system leads to significant water waste, resulting in high utility bills. Left unaddressed, continuous soil saturation can cause property damage, including erosion and harm to a home’s foundation. Understanding the source of the leak is the first step toward effective repair.
Locating the Source of the Leak
Locating the leak requires a systematic approach, starting with the water meter to confirm continuous underground flow. Turn off all water usage inside the home. The leak indicator on the water meter—often a small red or blue triangle—should be completely still. If the indicator spins, it confirms a leak exists, even when the irrigation system is inactive, which is useful for detecting leaks in the pressurized mainline.
Visual inspection of the landscape provides the next clue. Run the system zone by zone to observe above-ground components. Look for soggy areas, unusually lush grass, or standing water long after the irrigation cycle finishes. These saturated spots often point to a broken pipe or connection underneath. Homeowners should also inspect the valve boxes for standing water, which suggests a leak within the valve assembly.
Common Causes of Leaks in Sprinkler Heads and Pipes
The most common leaks involve physical components exposed to the elements or subject to underground stresses. Sprinkler heads frequently suffer damage from external forces, such as being struck by a lawnmower, vehicles, or heavy foot traffic. This impact can crack the plastic casing or damage the internal riser, causing water to spray unevenly or bubble up around the head when the zone is active. Worn-out internal seals and O-rings can also fail, allowing water to escape past the seal and pool at the base of the head.
Buried pipes, typically PVC or polyethylene, are susceptible to damage from ground movement, tree root intrusion, or the freeze-thaw cycle. When water inside a pipe freezes and expands, it can cause the pipe or fittings to split, resulting in a line break. A break in the lateral lines often results in a visible geyser or an oversaturated patch of soil between the heads. Another frequent cause is “low-head drainage,” where water remaining in the lateral line drains out through the lowest sprinkler head after the system shuts off due to gravity.
Hidden Leaks Caused by Valve Failures
Continuous leaks that occur when the system is supposed to be off are typically traced back to a faulty control valve. The primary component is a flexible rubber diaphragm, designed to seal against a valve seat when the system is inactive. If the diaphragm becomes brittle, cracked, or is prevented from fully seating by debris, the valve will “weep.” This allows water to continuously flow into the zone, exiting the lowest sprinkler head and creating a persistent wet spot.
The solenoid, a small electromagnetic coil that acts as the actuator for the valve, can also be a source of a leak if its plunger or O-ring is damaged. A faulty solenoid may fail to properly relieve pressure from the top of the diaphragm, causing the valve to remain partially open. Pressure regulation issues can also force a valve to leak if the system pressure is significantly higher than the components are rated for. This excessive pressure prematurely wears out the diaphragm and seals, leading to a slow, steady loss of water.
When to DIY Repair Versus Calling a Professional
Simple, above-ground repairs are generally manageable for the average homeowner with basic tools. Replacing a visibly cracked sprinkler head, unscrewing a broken riser, or tightening a loose fitting on a drip line are straightforward tasks. Homeowners can also clean a malfunctioning valve by disassembling the bonnet and removing debris that is preventing the diaphragm from closing. These repairs involve readily available parts and do not require specialized excavation or diagnostic equipment.
A professional should be consulted when the leak involves the pressurized mainline or is deep underground, requiring acoustic or other specialized detection methods. Mainline breaks, which are constantly under pressure, necessitate immediate repair and often involve working with larger pipe diameters and higher flow rates. Complex valve manifold repairs, issues with the backflow prevention device, or recurring leaks also signal the need for a technician. These situations require specific plumbing knowledge, pressure testing equipment, and expertise to ensure compliance with local water codes.