Maintenance is down to building managers if in the block of flats or the local authorities if it's a communal shelter. The block's shelters are used as cellars and the communal ones are used as a kind of cheap hostel for visiting school classes and the likes (I stayed in one when I went with school to Basel for Fasnacht) and that's where you can end up when you're doing your 3 weeks.

The overall control is exercised by "Protection Civile" which is a manned by those Swiss who can't be bothered/can't physically do national service, very bad for you liver with the constant "apero"...