Irrigation & Sprinkler Leak Detection

Mainline or zone? Why it matters

A sprinkler system has two kinds of buried pipe. The mainline runs from the backflow preventer to the zone valves and stays pressurized all the time, so a mainline leak wastes water even when the sprinklers are off. The lateral lines run from each valve to the heads and only carry water while that zone runs.

Knowing which one is leaking cuts the search down fast. Our guide to finding a sprinkler leak shows the meter test that tells them apart.

Signs you may need irrigation leak detection

• Soggy or sunken spots in the lawn
• One zone with weak spray, or heads that don’t pop up
• Water in the valve box, or water bubbling up near a valve
• A water meter that moves while the sprinklers are off
• A water bill that rises during the watering season

Common causes

• Freeze damage over winter, found at spring start-up
• Mower, aerator and landscaping damage to shallow lines and heads
• Roots pressing on lines
• Worn valve diaphragms that don’t fully close
• Cracked backflow preventers

How we locate it

1. Mainline testClosing the irrigation valve and watching the meter shows whether the always-on mainline is leaking.
2. Zone-by-zone testNarrows the leak to one zone.
3. Valve and backflow inspectionFinds valves that don’t close and cracked fittings.
4. Line tracing and acoustic listeningFollows the buried pipe to the break.

Want the details? Read how professional leak detection works.

Irrigation leak or main water line leak?

Both are buried in the yard, so they can look the same. If the meter stops when you close the irrigation valve, it’s the sprinkler system. If it keeps moving, the leak is in the house or in the main water line.

What to do before we arrive

• Close the irrigation valve and watch the meter to check the mainline.
• Run each zone and flag soggy spots or weak heads.
• Look inside the valve box for standing water.

After we find the leak

We flag the break and tell you whether it’s a head, a valve, a zone line or the mainline, so the repair is quick and targeted.

What affects the cost

The cost depends on the number of zones, the size of the yard, and whether the leak is on the mainline or a zone line. Detection and repair are quoted separately, and we can arrange both through our plumbing partner. See what affects leak detection cost, or call for a quote for your home.

Where we offer irrigation leak detection

We’re based in Bargersville and provide irrigation leak detection across Johnson County and nearby towns: Bargersville, Greenwood, Franklin, Center Grove, Whiteland & New Whiteland, Trafalgar, Nineveh & Prince’s Lakes, Morgantown and Southport & Perry Township.

Town pages for this service: Sprinkler Leak Detection & Repair in Greenwood and Sprinkler Leak Detection & Repair in Center Grove.

Frequently asked questions