Fuel is easy to carry, easy to sell and hard to trace. A few layers of low-cost control, plus good records, make theft harder and losses easier to spot.
Diesel and gasoline need no serial number, resale is simple, and an unattended tank or machine on a job site is often poorly watched at night and on weekends. Large equipment tanks and yard storage tanks hold a lot of fuel in one place.
Not all loss is outside theft. Some is internal: fuel taken for personal vehicles, fuel logged to the wrong unit, or fuel that disappears through casual practices. Good controls address both.
Even small amounts taken regularly add up, and thieves often damage caps, lines and tanks to get at the fuel, which leaves repair costs on top of the lost gallons.
Visible deterrents carry weight too. Signs stating that fuel is monitored and tanks are locked discourage opportunists.
Make the easy targets harder. A theft that takes a minute is far more tempting than one that takes ten.
Layer these measures where they make sense for your site:
Do not forget the delivery point. When a supplier's truck is filling a tank, someone from your side should know the delivery is happening and confirm the gallons afterward.
A storage tank that anyone can open is a tank that will lose fuel. Limit dispensing to named people, and require a record each time fuel leaves the tank: date, unit receiving it, gallons, and the name of the person who did it.
Pumps with electronic access keys or codes do this automatically and tie each transaction to a user. Even a paper log kept beside the pump is better than nothing, as long as someone reads it.
Rotate codes and keys when people leave, and keep a short list of who holds what. Shared codes that never change turn into a hole in the system. Separate duties where you can, so the person who fuels is not the only one who reviews the log.
Choose controls that fit how crews really work. A keypad pump takes seconds, while a lockbox across the site gets left open. Friction gets bypassed, so the best control is the one people will actually use.
You cannot spot a loss if you do not know what should be in the tank. A reconciliation compares three numbers: the starting inventory, what was delivered, and what was dispensed, against what is physically in the tank now. A persistent gap points to a leak, a metering error or missing fuel.
Do this on a regular schedule, and also compare each unit's consumption to its own normal. A machine that suddenly burns much more than before, or a fill that is larger than the tank can hold, is a flag worth chasing. The method is covered in fleet fuel management and reporting.
Read tank gauges at consistent times, such as the same hour each morning, and record the result. Compare electronic gauge readings with a physical check now and then, since a failed gauge can look like theft or hide it.
Tamper-evident seals only help if someone checks them. Make seal numbers part of the log so a swapped seal is noticed.
When fuel comes in on a supplier's truck and goes straight into a vehicle or equipment tank, it never sits in a place where it can be quietly drained. The delivery record names the unit, the product and the gallons. That reduces opportunities for diversion compared with cans and shared storage.
It also helps with keep-fill tanks. Delivery records give you the incoming figure for your reconciliation, so you can compare what the supplier put in against what your own dispensing log says came out. See bulk tank delivery for how that works.
Compare each machine's fuel use per hour of operation with its own history. A machine that burns more fuel for the same work hours is worth a look. Mechanical problems produce the same pattern, so check both explanations.
Look at patterns in time as well. Losses that cluster around weekends, holidays or particular shifts narrow the search quickly.
Job sites change from week to week, which makes fixed fencing impractical. Mobile options include lockable site tanks, well-lit equipment parking and sharing the end-of-day fuel level with the site lead.
Another simple habit is to have operators note the fuel level at the end of each shift, so a drop overnight stands out the next morning. Our job site equipment fueling can be timed accordingly.
Tell the crew what the controls are and why. Controls that are explained are respected more, and people are more willing to report oddities when they know someone is watching the numbers.
Document what you found: photographs, tank readings, and the time you discovered it. Report it to local law enforcement and to your insurer, and review your logs and any camera footage. Do not confront suspects. Also check the area for spilled fuel, since siphoning can leave a release that has its own reporting duties, as explained in job site fuel spill prevention and response.
A short closing checklist for the person locking up each night keeps the routine from depending on memory: lights on, caps locked, tank locked, gate closed.
Locking fuel caps and a locked fill port, combined with a simple dispensing log that someone reviews.
Visible cameras can deter some theft and help investigations, but they work best with lighting, locks and regular reconciliation.
Reconcile starting inventory, deliveries and dispensing against the tank level, and compare each unit's use to its own normal.
It can, because fuel goes directly into equipment with a record of each fill, so less sits in cans or open storage.
Tell us what you run and where it sits, and we will come back with a delivery plan.