You pay service costs on top of your basic rent. The service costs include for example the cleaning costs of the common areas, the electricity costs for lights in the common hallway or the maintenance of an intercom system or elevator. The service costs also include the maintenance costs of a communal garden and the cleaning costs of the exterior of your windows.
The service costs are advance payments, based on an estimation of the actual costs. At the end of the year, we'll check whether you have to pay extra, or get a refund. You'll find an overview of this in the service costs settlement. Normally you receive this bill in July.