How We Caught an Irrigation Leak Without Getting Our Boots Wet

Water is the most precious resource we manage at Ballarat Advanced Tree Nursery. We have tens of thousands of trees and plants in various stages spread across the property. Each tree row has its own irrigation zone running on a timed and automated irrigation schedule. Our pumps cost a serious amount of money, their life is lessened every time they cycle on and off unnecessarily. Getting the watering wrong doesn't just mean a dead tree. It means wasted water, shortened pump life and costs that add up fast.

Some of you might know I love technology and automations. So I did what I do best and built systems and automations to ensure we can manage our irrigation. It means I can monitor and find leaks and problems fast to get them fixed before they cost us in repairs and wasted water.

Watch me find and fix the leak in my YouTube video.

It All Starts With a Solenoid

Our irrigation setup runs on a network of solenoid valves, each one controlling a zone across the nursery. For those of you new to irrigation let me start at the beginning, because I can hear you asking: but Nathan, what is a solenoid? A solenoid is essentially an electrically operated water tap. When the controller sends a signal down the wire, the valve opens. When it stops, a spring-loaded rubber diaphragm seals the orifice shut and the water stops.

For us the whole system is managed from central automated irrigation controllers, which schedule every zone, every cycle, every duration all based on the weather variables such as the sun, wind, rain and evaporation. Our pump runs from 5am to 5pm on watering days, supplying water through zones in sequence. It's efficient and automated, which is one less thing for us to have to manually worry about or do each day.

On top of the scheduling, we also have energy monitoring on the pump, and that is how this video came about.

The Graph That Spotted the Problem

So it's Sunday in winter, and Ballarat has had a few weeks of decent rain and everything is well watered. There has been no need for the irrigation to turn on and off. The pump had no reason to be doing anything, right?

But when I pulled up the energy monitoring graph for Saturday, it told me a different story. Instead of a flat line (pump off, no activity), there were regular little spikes throughout the day. The pump was cycling on and off repeatedly, trying to maintain pressure in a system that should have been completely idle.

Which likely means just one thing: there's a leak. The system was loosing pressure somewhere and the pump was working to compensate.

Tracking It Down

So with the data telling me this, the next step is figuring out where it is and isolating it. There are a couple of ways to do this. One is working through the zone valves in the pump shed one at a time, which can be a bit time consuming, or you can just do a manual inspection of the lines and look for obvious signs. I chose the latter.

What this looked like was a drive around the nursery looking at the sprayers and seeing if any were dripping. Since the irrigation is turned off, all of the sprayers should be dry. It honestly didn't take me too long to find the culprit: a sprayer in row one, with that zone's valve closed and no irrigation scheduled. The valve was supposed to be sealed and it wasn't.

A Piece of Plastic. That's It.

So we talked about solenoids before: they are basically a water tap at each point of our irrigation line. The pipe that feeds those sprayers goes underground and comes up at a solenoid block. When I pulled the solenoid block apart, the culprit was immediately visible: a small piece of plastic had made it through the system and lodged against the rubber diaphragm. The diaphragm is the part that presses down onto the orifice to seal the water flow. The piece of plastic had been sitting there long enough to put a dent in the rubber.

Unfortunately, once the rubber is dented it doesn't seal flat anymore. Water finds the gap and keeps moving through, even when the valve is closed. So I had a go at cleaning it out, but instinct told me it would need to be replaced, and sure enough once I reassembled the unit to test it, the leak was still there. The rubber needed to be replaced.

The Frustrating Cost of Spare Parts

With the problem officially diagnosed, the next step is repair. Something worth knowing if you run any kind of large irrigation system: the replacement rubber diaphragm for the solenoid blocks we use costs more to buy as a spare part than a whole new solenoid unit does.

We use the Hunter PGV101GB solenoids. They're made in Mexico and they're good quality. Parts are available through Hunter's network. But that little rubber piece on its own, sourced separately, comes in at more than the price of the whole block, which is not only crazy but financially frustrating.

So the fix was to open a brand-new solenoid, take the rubber from it, install it into the existing block, and put the rest of the new unit on the shelf for spare parts to use at a later time. Forty to fifty dollars for the new unit, with most of it going into storage for a future repair.

Not ideal. But it's the reality of commercial irrigation maintenance.

Getting Things Back Up and Running

With the new rubber in and the system repressurised, the sprayer stopped dripping. I checked the energy monitoring graph the following day to confirm the pump had stopped cycling, and it was reassuring to see it tracking flat. If it had still been showing spikes, that means there's another leak somewhere, and so we just start the process again.

This is a system that works for us. We monitor the data, which means we can identify issues quickly, isolate the cause, fix it, and move on. No guessing, no waiting until a zone is visibly failing, and no trees going dry while a fault goes unnoticed.

Why This Matters for Our Trees

Our trees get the water they need and the pump isn't wasting energy cycling when it doesn't have to. Both matter at our scale. Not to mention, every litre of water lost through a leaking solenoid is water that doesn't go to a tree and doesn't come back. For a nursery operating at our scale, small leaks have real consequences and cost.

The monitoring system we run means we catch these issues fast. What could have been weeks of wasted water and pump wear was picked up in one morning. Most people find out something's wrong when a tree starts dying. We found out on a Sunday morning before anything was affected.

If you're thinking about your own irrigation setup, whether for a home garden or a larger property, this kind of monitoring isn't complicated to set up. The hard part is actually looking at the data. Do that, and you'll catch problems before they cost you.

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