Substandard apartments mainly consist of a kitchen and a room (sometimes also a half-room) and have, depending on the category, a simple (Category C) or no water supply (Category D). In the case of Category D apartments, the toilet is located in the hallway. In Vienna, the stock of substandard apartments has declined significantly in recent years because many of these apartments have been renovated and merged together. Nowadays, substandard apartments play hardly any role in new tenancies.