Many people choose to say goodbye to their oil tank and switch to other, more sustainable ways of heating such as natural gas or a heat pump. When you want to have your heating oil tank decommissioned, there are some important aspects to consider. Is it an above-ground or underground tank? What is the capacity of the fuel tank? Does the tank need to be removed or is it enough to fill up? In this blog, you will read everything you need to know about decommissioning your fuel oil tank.

When you no longer use your oil tank, you are legally obliged to have it decommissioned by a recognised professional. Above all, do not do it yourself, because cleaning your oil tank is not entirely without risk and requires specific expertise and know-how. Moreover, do not put off cleaning your oil tank for too long. Otherwise, you run the risk of soil contamination, which can entail sky-high costs.

If you plan to sell your property, the buyer may demand a certificate of decommissioning. This certificate shows that the oil tank was removed/cleaned in a professional manner. As a seller, you are not obliged to provide this certificate, but it is a great added value for a smooth sale of your property.

Also note that an out-of-use oil tank should never be used to collect rainwater or as a drinking trough for livestock. The tank should only be used to store the product for which it was built.

The Flemish government does not currently provide subsidies for the removal of fuel tanks, but be sure to check with the city or municipality where you live. It is possible that they do provide subsidies.

Less than 6000 litres

• Emptying and cleaning mandatory
• Removal not mandatory

If it is an above-ground fuel oil tank with a capacity of 6,000 litres or less, you, as the owner, are obliged to have the tank pumped out and cleaned. There is no obligation to have the tank physically removed.

If you do decide to have your above-ground fuel oil tank removed, for example to free up space, the fuel oil technician carrying out the works is obliged to issue a decommissioning certificate. Such a certificate indicates that the work was carried out according to the rules of the trade and it always includes the name of the fuel oil technician and his/her approval number. Without a certificate of decommissioning, it is not possible to dispose of the tank to a waste processor. 

If you only have the heating oil tank emptied and cleaned, the technician is not obliged to issue such a certificate. At Vastgoedexperts, we do provide a cleaning certificate in that case, which allows you to dispose of the tank yourself to a waste processor in the future.

More than 6,000 litres

• Emptying and cleaning mandatory
• Removal mandatory (if removal is impossible, just empty and clean)
• Deadline: within 3 years

For above-ground oil tanks of more than 6,000 litres, different rules apply than for the smaller ones. Tanks of that size must always be emptied, cleaned and removed within three years of the tank no longer being used. If removal is impossible due to specific circumstances, the tank must only be emptied and cleaned. This must always be done by a certified fuel oil technician. He or she is obliged to issue a certificate to the owner after the work.

Less than 6000 litres

• Emptying and cleaning mandatory
• Removal mandatory (filling if removal is impossible)
• Deadline: within 5 years (before next periodic check-up)

Speaking of an underground tank with a capacity of 6,000 litres or less, you are not only obliged to empty and clean it, but in principle the tank must also be excavated. If this is not possible due to circumstances, for example if the tank is too close to the house and therefore there is a risk of stability problems, the tank can also be filled with sand, foam or an equivalent filler. Similarly, if the tank is too close to utility lines, the fuel oil tank can be filled rather than excavated. 

The work must be carried out before the next periodic inspection. In other words, within five years of the tank no longer being used.

Attention, we speak of an underground heating oil tank only when it is fully buried in the ground. A heating oil tank in the basement is therefore considered an above-ground tank. 

More than 6,000 litres

• Emptying and cleaning mandatory
• Removal mandatory (filling if removal is impossible)
• Deadline: within 3 years

Do you want to have your underground tank of more than 6,000 litres decommissioned? Then you are also obliged to have the tank emptied, cleaned and removed. Only if there is a risk of stability problems can the tank be filled without having to be completely excavated. 

So the same process as for an underground tank of less than 6,000 litres. The only difference is the period within which the works must be carried out. In the case of a fuel oil tank of more than 6 000 litres, this must be done within three years of the tank no longer being used; in the case of smaller heating oil tanks of less than 6 000 litres, the deadline is five years.

When excavating/remediating an underground fuel oil tank, the technician carrying out the works is always obliged to issue a decommissioning certificate, regardless of its content.

Different rules then apply to fuel oil tanks that were used for non-occupied buildings such as schools, offices and hospitals. The same applies to oil tanks that were used for other purposes, such as supplying motor vehicles. 

If above ground, the tank should be emptied, cleaned and removed. If removal is impossible due to circumstances, it is sufficient to empty and clean the tank. 

The same obligations apply to an underground tank. If removal is impossible, the underground tank can also be filled with an inert material such as sand or foam. The work must be carried out within three years of the tank no longer being used. This deadline applies to both above-ground and underground fuel tanks. 

As mentioned earlier in this blog, it is not advisable to remove or fill your heating oil tank yourself. You will not have a certificate of decommissioning, and there are also a lot of health risks involved. That is why there are strict guidelines for cleaning a fuel oil tank. We list them for you:

1. Emptying the fuel tank: all residual fuel is sucked out of the tank
2. Sediment removal: there is often still sediment at the bottom of the tank. This should also be removed and disposed of with the tank.
3. Cleaning fuel oil tank: The technician cleans the tank with appropriate products. Afterwards, he/she ensures that the dregs and waste water are disposed of properly.

If you decide to decommission your fuel oil tank, there are many things to consider. So inform yourself well before making a final decision. Always consult an expert first who can advise you and carry out the work correctly. That way, you are sure to be in order with all the certificates and avoid unnecessary worries in the future.