Commercial Irrigation Leak Detection

How a leak stays hidden for a year

Most irrigation leaks on commercial property are not dramatic. Nothing sprays into the air and no area floods. That is exactly why they persist.

A mainline leak runs continuously, twenty four hours a day, whether the system is scheduled or not. On a slope, or in coarse soil, the water disappears underground and never surfaces. The only evidence is on the bill.

A valve that no longer seats does the same thing on a smaller scale, running quietly between cycles. It often shows as a patch that is always damp, which gets blamed on drainage.

Neither is visible during a normal maintenance visit, because a maintenance visit happens while the system is off.

A mainline leak runs continuously whether the system is scheduled or not. The only evidence is on the bill.

How they get found

The most reliable first test costs nothing. Shut the irrigation off entirely for an hour and read the meter at the start and end. Any movement with everything off is a continuous leak on the mainline or through a valve.

That single test separates a continuous leak from a scheduling problem, which is the most useful distinction there is, and most properties have never done it.

Isolating it comes next: closing sections and repeating the test narrows the leak to a run of pipe. From there, listening equipment or careful excavation finds the point.

Zone by zone, the method is different. Run each zone and watch for the pressure drop that indicates a break, and look for the wet or unusually green area that a lateral leak produces.

1. Shut off all irrigation and read the meter over an hour
2. Any movement means a continuous leak, not a scheduling issue
3. Close isolation valves in sections and repeat to narrow the location
4. Run each zone individually and watch for pressure loss
5. Look for areas that are always damp or unusually green
6. Repair, then repeat the meter test to confirm

Why this is worth doing before anything else

A continuous leak is the most expensive fault in irrigation because it does not stop. Everything else wastes water for the minutes a zone runs. A leak wastes it for every minute of the year.

It also invalidates every other efficiency effort. A property that installs a smart controller while a mainline leak runs will see very little change in the bill and reasonably conclude the controller did not work.

This is why leak detection sits at the front of the sequence. Fix what runs continuously, then fix what runs on schedule, then improve the schedule, then upgrade the hardware.