In order to protect ground and water from pollution oil tanks holding more than 1 m³ and used for diesel, heating or waste oil are to be inspected regularly.
As a property owner or activity operator you are responsible for informing/reporting or applying for permission and making sure that the recurring inspections are made at the right time.

Property owners are responsible for oil tank inspections being made according to the following:

The inspection regulations also contain demands on equipment and technical appliances. In connection with installations and recurring check-ups inspections must be made by an accredited inspection authority, and a copy of the inspection report must be submitted to Samhällsbyggnadsförvaltningens myndighetsenhet (the Authority Unit of the Community Planning Department). There is no report obligation for indoor tanks. You can find inspection firms in the telephone directory Yellow Pages under "Oljesanering, Tankrengöring".

If the tank is not in use, it must be emptied and cleaned. This should be done by an accredited company. Fill the tank with sand or dig it up, disconnect the filling pipe and submit a certificate of what measures have been taken to the Authority Unit.