An underground irrigation leak hides in plain sight — a soggy patch, weak heads, a creeping summer bill. Here is how to spot a sprinkler line leak, what causes it, and how we locate and repair it without trenching your yard.
Written bySteven Lockhart·Reviewed byMiguel Lopez, Owner & Licensed Plumber (CSLB #974600)·Last reviewedJune 2026 · 5 min read
Quick Answer
A sprinkler or irrigation line leak is an underground leak in your yard's water lines — often showing up as a soggy or unusually green patch, weak sprinkler pressure, or a summer water bill that jumps. New Pro locates buried irrigation leaks with line tracing and pressure testing, then repairs the exact point rather than trenching the whole yard.
Irrigation lines run buried and under pressure, so a leak rarely shows as an obvious spray — it shows as a patch of lawn that is too green or never dries, a zone with weak heads, or a summer bill that climbs. Because the water disappears into the soil, locating it precisely is what keeps the repair to a single dig. This page is part of our complete guide to water leak detection in West Los Angeles.
A sprinkler / irrigation line leak is an escape of water from a buried irrigation supply line, valve, or fitting — detectable by soggy ground, uneven head pressure, or a rising outdoor water bill before it is ever visible.
Irrigation leaks give themselves away above ground. The table maps each sign to its likely cause.
| Sign | Likely cause | What we check |
|---|---|---|
| Soggy or muddy patch | Cracked lateral or fitting below it | Trace & pressure-test that zone |
| Unusually green strip | Constant water feeding the grass | Locate the line under the strip |
| Weak / uneven heads | Pressure loss from a break upstream | Isolate the zone & find the break |
| High summer bill | Continuous underground loss | Meter test, then locate the leak |
| Bubbling at a valve box | Failed valve or manifold fitting | Inspect & repair the valve assembly |
Most yard-line leaks come from age and movement — brittle old PVC or poly pipe, fittings that loosen as soil shifts, root pressure from nearby trees, or a head sheared off by a mower. On the Westside, mature trees and decades-old irrigation are the usual story. We find the failure point and repair or replace just that section.
Locating a buried irrigation leak keeps the repair to one targeted dig instead of trenching the yard.
We run each irrigation zone to find which one is losing pressure or feeding the wet area.
We pressurize the suspect line to confirm the leak and gauge its severity.
We trace the line and pinpoint the break or failed fitting under the surface.
We dig the one located spot, repair or replace the section, and restore the line.
Not sure what you are looking at? We will pinpoint it before opening a wall.
Get a Free QuoteA Culver City homeowner notices one corner of the lawn is always soggy and the summer water bill has climbed for no clear reason.
New Pro isolates the irrigation zones, pressure-tests the suspect line, and traces a cracked lateral to a single point under the wet patch.
The line is repaired through one small dig, the lawn dries out, and the next bill drops back to normal — no trenching across the yard.
The Bottom Line
A sprinkler line leak quietly wastes water and drowns part of your yard long before you see it. The fix is to locate the break precisely, not dig up the whole irrigation system. New Pro traces and pressure-tests the line, repairs the one failed point, and quotes a flat rate first. Call any time.
Look for a patch of lawn that stays soggy or is unusually green, a zone with weak or uneven heads, bubbling near a valve box, or a summer water bill that climbs with no change in watering. A meter test with the irrigation off can confirm water is escaping underground.
Yes. We isolate the zones, pressure-test the suspect line, and trace it to pinpoint the break, so the repair is one targeted dig rather than a trench across the lawn.
Usually age and movement — brittle old PVC or poly pipe, fittings that loosen as soil shifts, root pressure from nearby trees, or a head sheared off by a mower. Mature Westside landscaping and decades-old irrigation are common factors.
It can, noticeably — especially in warm months when irrigation runs most. Because the water goes straight into the soil, an underground irrigation leak often shows up first as a higher summer bill before the wet patch is obvious.
Both. Once we locate the break we repair or replace that section and restore the line. If the system is failing in multiple places we will tell you honestly whether spot repairs or a larger fix is the better value.
Not always — poor drainage, over-watering, or a downspout can also keep ground wet. That is why we confirm with a meter test and a pressure test before locating, so you are not paying to dig for a problem that is not a leak.
Written by the New Pro Plumbing content team and reviewed for technical accuracy by Miguel Lopez, owner and California-licensed plumber (CSLB #974600). Statistics are cited to the U.S. EPA and figures reflect typical West LA conditions, not a quote — we confirm pricing in writing before any work begins.
What's new: June 2026 — first publication.
We trace and pressure-test irrigation lines to pinpoint the break, then repair the one spot — flat-rate price before we start. Call any time.
