How to Find and Fix an Underground Irrigation Leak
An underground irrigation leak is one of the trickiest problems — it wastes water silently, out of sight, until your bill or a soggy spot gives it away. Here's how to find and fix a hidden sprinkler line leak.
Signs of an underground leak
- A soggy or unusually green area that stays wet between waterings.
- Low pressure in a zone, since water escapes before reaching the heads.
- A spinning water meter when all water is off.
- An unexplained jump in your water bill.
- Sunken soil, eroding mulch, or small sinkholes.
Narrow down the location
First confirm it's the irrigation system: shut off the irrigation supply (but leave house water on) and watch the meter. If it stops, the leak is in the sprinklers. Then run one zone at a time to find which one loses pressure or produces a wet spot — that isolates the leaking zone.
Find and expose the leak
Within the suspect zone, look for the wettest spot or where water bubbles up. The leak is usually at or near there — a cracked pipe, broken fitting, or failed valve. Carefully dig down to expose the damaged section.
Repair the line
Cut out the damaged PVC and splice in a new piece with couplings (or use the appropriate fittings for poly tubing). Let glued joints cure, then restore water slowly. Check that the repair holds and pressure returns.
When to call a pro
Hidden leaks — especially on the mainline or under hardscape — can be hard to pinpoint. Our irrigation team has the tools to locate and repair them fast.
Frequently asked questions
How do I find a hidden sprinkler leak?
Isolate the irrigation system at the meter, then run zones one at a time to find which loses pressure or creates a wet spot.
Can a small irrigation leak waste much water?
Yes — even a small underground leak can waste hundreds of gallons over time and steadily raise your bill.
Arbol Roble has cared for Inland Empire landscapes since 1997, serving Rancho Cucamonga, Ontario, Fontana, Eastvale, Corona and Riverside. Request a free quote or browse our residential and commercial services.
About the Author
The Arbol Roble team are licensed landscaping and irrigation professionals (CSLB License #1077455) serving Rancho Cucamonga, Ontario, Fontana, Eastvale, Corona, Riverside, and the greater Inland Empire.