When I first started experimenting with ways to measure tank levels, I didn’t reach for fancy industrial sensors or cloud dashboards. In typical “Me” style, I reached for the back of my ute. Specifically, the reversing sensors.

They seemed perfect — cheap, waterproof, and already designed to measure distance. I figured if they could tell me how close I was to old mates fancy new 79 series at the woolies car park, they could probably tell me how close the water surface was to the top of the tank. And at first, it worked. The readings came through clean and surprisingly accurate. For a few glorious days, I thought I’d outsmarted the industry with a handful of spare car parts.

Then it rained.

The next time I checked the data, it looked like my tank had turned into a trampoline. The water’s surface was dancing, the readings were bouncing, and the sensor had absolutely no idea what was going on. A quick bit of research reminded me that reversing sensors rely on ultrasonic pulses — little sound waves that reflect off nearby surfaces. Great for flat, solid things like concrete. Not so great for rippling water during that summer storm.

And as if that wasn’t enough, after a few days of humid weather, condensation formed inside the tank…and then onto sensor housing. Moisture in the wrong place can really confuse an ultrasonic transducer. My readings started jumping between “nearly full” and “completely empty” faster than a dodgy kingswood fuel gauge.

In the end, the reversing sensor went back to its rightful place — on the bumper — and I went hunting for something a bit more serious. That’s when I landed on pressure transducers.

Instead of measuring distance from above, they measure the pressure at the bottom of the tank. Because water pressure increases predictably with depth, you get a rock-solid reading regardless of surface movement, rain, or condensation. They’re sealed, reliable, and blissfully unbothered by the weather.

Switching to a pressure-based system was one of those moments where simplicity won. It might not sound as clever as hacking car parts, but it actually works — and keeps working.

So yes, reversing sensors can work in a water tank, just long enough to teach you why they shouldn’t. Sometimes, the hard way is the best way to learn.