Who bears the cost of renting smoke alarm devices?

Can owners pass on the rent and maintenance for smoke alarm devices (RWM) as part of the operating costs billing?

In Baden-Württemberg, according to Section 15 (7) of the Landesbauordnung (State Building Code), the owner is obliged to equip apartments with smoke alarms if they are rented out. The regular obligation to inspect is initially the responsibility of the tenant, whereby the owner can do this by simple explanation in order to counter possible liability risks.

The landlord is not entitled to a "rent smoke alarm" payment, because by law he is responsible for the equipment. You are free to buy or rent RWM.
At first glance, the rental costs for RWM could be running costs, but actually they are "hidden" acquisition costs, which the landlord alone has to bear according to §535 (1) BGB.

The annual inspection and maintenance costs, however, are undisputedly to be passed on to the tenant, provided that the landlord has taken on the obligation to inspect and assigns this task to a service provider.