Declaring your oil tank


The legislation applies to tanks with a capacity equal to, or greater than, 3,000 litres, comprising one or more reservoirs, whether overground (i.e. in the garden, cellar or in an uncovered pit) or buried (i.e. buried directly in the ground or in a fully or partially covered pit).

After 25,000 litres, tanks are subject to the environmental permit (see “connected processes” section: Applying for an environmental permit or a single permit for a class-1 or class-2 establishment).

For tanks with a smaller capacity then 3.000 litres, these rules are not mandatory; however, it is highly recommended.

In drinking water catchment prevention zones, these deposits must comply with the AGW requirements of July 17, 2003.

Key points

  • Confronted with a leak from your home oil tank? Call on the PROMAZ Fund until February 28, 2025. The PROMAZ Fund can, under certain conditions, intervene financially for the clean-up of a leak from an oil tank and/or its pipes, whatever the capacity of the tank.
  • The technician who checks the deposit must be approved in the Walloon Region. It is left to the free choice of the citizen. It is possible to practice a counter-expertise of the control or to request several quotes for the works.
  • If it is not possible to prove the actual capacity of the deposit (by a purchase invoice, a volume invoice for a full tank - full of 2850 liters equivalent to a tank of 3,000 liters minus the role of the whistle - , result of a strapping of tank, etc), then it will be considered as being of a capacity higher than 3.000 liters and will be subjected to obligatory declaration and periodic control.
  • If the tank is no longer used (particularly following a change of energy carrier - switch from fuel oil to town gas and therefore change of boiler as well), it must be permanently decommissioned. The tank must be emptied, cleaned, degassed and removed or inerted only if the tank is buried. In other words, whether the tank is above ground or buried, final decommissioning requires emptying, cleaning and degassing. The sludge resulting from cleaning must be evacuated by an approved “hazardous waste” collector/transporter. Following these operations: the aerial tank must be removed and evacuated; the buried tank must be removed and evacuated or inerted; the pipes must be emptied, dismantled and evacuated.

In detail

  • Either go directly to the municipality and find the declaration form; 
  • Or download the PDF form in the forms section below
  • Or complete the form directly online (see the forms section below). Once the form is complete, a PDF will be generated and no further action is required. The municipality will be updated automatically.

If you complete the form online (they are only available in French), there are 3 important pieces of information that must be provided:

  • The category number: for tanks between 3,000 and 24,999 litres;
  • Cadastral references;
  • Download an installation diagram for the tank. This may be done freehand, but it is a good idea to have a scanner at home to download this document.



Contact the tank service of the Soil Protection Department - Only available in French
Updated on
Process n° : 2514
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