Recently the Italian Supreme Court has sentenced that garrets not suitable for common usage belong to the owners of the dwellings positioned below. These spaces may be transformed into living areas, which is particularly convenient in this moment of housing shortage. In this study the authors analyze the minimum hygienic requirements for transformed garrets established by each regional law, and underline the considerable differences authorized by the laws. For example, there is a tolerated difference of +/-0,4 m for the the minimum height, and therefore there is a large variability accepted for the volumes of the rooms, namely a tolerated range of 3,6 m3 per capita in single rooms and 2,8 m3 per capita in double rooms; such accepted values are very close to (and sometimes below) the limits for living spaces that have been recommended by the international community. Finally, the authors stress the importance of planning sanitary interventions to protect the health of the inhabitants of those dwellings.