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Hampshire Trading Standards

At the Filling Station

There is legislation requiring all pumps to be clearly marked, however, there is no requirement to use any colour coding.

Due to the larger nozzle, it is very difficult to fill a petrol car with diesel, however, it is all too easy to fill a diesel car with petrol.

If you are filling an unfamiliar vehicle, or have petrol and diesel powered vehicles in your family, take a moment to consider which fuel you require before selecting the hose.

If you do re-fuel with the wrong product, inform the cashier what you have done, do not start the engine but get the car pushed to a safe place on the forecourt and call your breakdown service or a local garage. If your car has central locking, do not operate this because unlocking can cause automatic priming of the fuel system in some cars.

If you do start the engine or drive with the vehicle in this state you may expect a very large bill for repairs!


How do you know you are receiving the correct amount of fuel?

When a pump is installed, it is tested to check that it delivers the correct amount of fuel. When officers check equipment they make sure the measures are within legal tolerances (that is between - 0.5% and + 1%)

The pumps are ‘sealed’ to ensure they cannot be tampered with. Each time any maintenance is carried out or parts need replacing, the testing procedure is carried out again. We also carry out unannounced checks.

The quantity delivered must be within legally defined tolerances.

If there are serious complaints or concerns with a pump, then Trading Standards Officers have powers to investigate, issue notices to bring the equipment back to legal compliance or, if necessary, put the pump out of use until the issues are put right.

If you believe a pump you have used is incorrect we would like to hear from you.


  • Always check the displays return to zero before starting your delivery
  • If the display advances before you have delivered any fuel replace the nozzle and let the kiosk staff know.
  • Make sure you are buying the grade of fuel you want. All garages advertise the price of ordinary unleaded fuel on the road side sign. Many also sell a higher grade of petrol, but this is more expensive. Check the unit price displayed on the pump is what you want to buy. The same is true for different grades of diesel.
  • Note the price to pay when you have replaced the nozzle. This should be the same price as displayed in the kiosk. Sometimes the pump display will jump a penny between finishing delivery and replacing the nozzle. This can happen for a number of reasons and gets more likely as the price of fuel increases.


We sometimes receive complaints from motorists who find that on replacing the nozzle in the pump that the price indicator ‘runs on’ by an additional 1p.

Measurement of fuel in a petrol pump involves the pumped fuel causing a ‘pulser’ to rotate and send a signal to a processor (computer). The customer display shows the quantity delivered and the price as calculated by the computer.

Because the price of petrol is now so high, a very small movement in the pulser can be enough to trip the price indication by a penny. In reality, this represents only a very small quantity of petrol – about a teaspoonful in fact. The running on can be caused by simply just passing the precise quantity through normal delivery, or when the nozzle is replaced, the internal volume of the hose can change due to internal pressure forcing more fuel into the hose. This effect is called ‘hose dilation’ and is simply the hose swelling slightly. The error in such cases, if any, is very minor and well inside the permitted pump error tolerances of -0.5% to +1.0%.

Before a pump can be put into use in the UK, it must be granted a Certificate of Approval issued by the National Weights and Measures Laboratory. Part of the Laboratory’s approval process is that they must be satisfied with the method of price computation.

The solution

As long as the price of fuel remains high, this phenomenon will continue to happen. There is no cure for the problem, but it may be some reassurance to know that as a customer you are not receiving short measure.

Some garages now have ‘penny boxes’ on the counter where some customers place the odd pennies when their transactions have ‘run on’ and that other customers, who are confrontational about the extra penny, take a penny out. This has been found useful in avoiding problems.


If you are splashed with petrol while filling you car, the cashiers should be trained to deal with this situation.

They should offer you the facility to wash and may be able to provide a disposable suit for you to wear and a plastic bag to seal your clothes.

Do not smoke or approach sources of ignition until you have ensured the petrol has been cleaned off. Do not attempt to dry yourself off in front of a radiant heater.

Any petrol spilled on the ground should be covered with sand or granules and cleared up by the site staff. If the petrol has splashed into your eyes, or you display an allergic reaction, seek medical advice urgently.


How to report a product problem

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