Anyone who owns a detached house is familiar with the problem: when assessing the property for council tax purposes, the tax office uses a figure for living space that the owner considers to be too high. A recent ruling by the Berlin-Brandenburg Tax Court makes it clear that not every basement room is automatically to be classified as living space.
What was the dispute about?
The proceedings concerned the valuation of a detached house for the purposes of property tax. It was undisputed that the above-ground living space amounted to approximately 147 square metres. The basement, which was entirely underground, also contained a room measuring 26.44 square metres. This room had a clear height of 2.10 metres, was heatable and had a small window which allowed daylight and fresh air in only via a barred light well. The room was used as a storeroom.
The tax office simply included this basement room in the living space, arriving at a total area of 173 square metres. The owners successfully challenged this decision.
What was the court’s ruling?
The Berlin-Brandenburg Finance Court clarified that the Residential Floor Area Ordinance (WoFlV) is the governing legislation for calculating living space under the standardised income approach. Under this Regulation, basement rooms that have not been converted for permanent residential use are regarded as so-called ancillary rooms. These are excluded from the calculation of living space.
In this specific case, the basement room lacked the necessary facilities for residential use: there was no floor covering, and the ventilation and natural light were inadequate. The court therefore classified it as a typical ancillary room, which is not to be included in the living space. The higher floor area assessed by the tax office was therefore incorrect.
What is the basis for the property tax valuation?
Under the Valuation Act, detached houses are valued using the standardised income approach. The property tax value is calculated on the basis of the capitalised net yield and the discounted land value. The net yield depends, amongst other things, on the living area. The larger the assessed living area, the higher the property tax value tends to be, and consequently the higher the tax burden.
What does this mean for property owners?
This decision has practical implications for all owners of detached houses or flats where the tax office has included basement rooms in the calculation of living space. Anyone who has received such a notice should check whether the living space used as a basis is correct. The decisive factors here are not merely the ceiling height or whether the room can be heated, but the room’s overall fittings and its actual suitability as living space.
If a basement room is used solely as a storage room or warehouse and lacks proper flooring as well as adequate ventilation and natural light, it is unlikely to be classified as living space under current legislation.
The judgement of the Berlin-Brandenburg Finance Court was handed down on 3 March 2026 under case number 3 K 3118/25. In individual cases, it is advisable to seek tax advice in order to check your own property tax assessment for any errors.
Source: Haufe: Tax
This post and the accompanying image were created with the help of AI and have been editorially reviewed.
