Most fleet managers know they're losing fuel. The signals are obvious — fuel costs creeping up without a corresponding increase in distance, drivers buying suspiciously low quantities at suspicious stations, the same vehicle averaging two very different consumption rates depending on the driver.
But knowing fuel is being stolen and proving it are two different things. And until you can prove it, you can't act.
The three patterns of fleet fuel theft
In our experience deploying FuelPortal, fuel theft falls into three patterns:
1. Mid-route siphoning. The classic. Driver stops in a quiet area, siphons 30–80 litres into a jerry can, sells it. Hard to detect with fuel-card data alone because the tank fill is legitimate — it's the drain hours later that matters.
2. Inflated receipts. Driver fills 200 litres but the receipt reads 250 litres. The forecourt attendant gets a cut. Without verified tank-level monitoring, the difference is invisible.
3. Card sharing. Driver uses the company fuel card to fill personal vehicles or family vehicles. Often combined with kickbacks at preferred stations.
What detection actually requires
It takes four measurements of the same litre, held against each other:
- What was paid for — the fuel card transaction or the till slip.
- What left storage — the tank-level sensor on the depot tank or bowser.
- What the pump dispensed — the flow meter on the outlet.
- What the truck received and burned — a calibrated tank sensor in the vehicle, not the OEM gauge, alongside consumption read off the engine.
Every one of them is positioned and time-stamped. When the four agree, fuel use is normal. When the level drops faster than the engine can account for — at a specific place, at a specific time — you have a drain event. When a pump dispenses litres that never arrive in a truck, you have a ghost fill.
That's the entire mechanic. FuelPortal automates it across the fleet, flags discrepancies, and produces a per-driver report, with each event carried at the time it happens.
What it doesn't catch
Drivers occasionally swap fuel between tanks, run engines unnecessarily to mask theft as 'idle consumption', or work in pairs to fake fills. No system is perfect. The point is to make the theft expensive — in time, coordination, and risk — relative to its reward. Most operators see a 20–30% drop in unexplained fuel consumption in the first 90 days.
That's not theft eliminated. That's theft becoming uneconomic.
If you want to know what this would take on your own fleet, tell us about it — the tanks, the pumps, the vehicles — and we will tell you straight whether it is a fit.