Does the owner have the responsibility to change the bedroom into a bathroom property without authorization?

Property must have the responsibility to supervise.

You can ask the property owner to restore the original state. If you refuse, you can submit it to the Construction Bureau for handling. If not, the owners' committee may file a lawsuit for compulsory restoration. If there is no owners' committee, it may be filed by the property after soliciting the opinions of the owners.

There are also some prohibitions, such as changing the main body and load-bearing structure of the building, expanding the load-bearing, expanding the size of doors and windows, and wasting energy, which are also absolutely prohibited.

Extended data:

Provisions on housing renovation in the Measures for the Administration of Interior Decoration of Residential Buildings;

Article 5. The following acts are prohibited in residential interior decoration activities:

1. The main body and load-bearing structure of the building are changed without the original design unit or a design unit with corresponding qualification grade;

2. Change rooms or balconies without waterproof requirements into bathrooms and kitchens;

3. Enlarge the original size of the doors and windows on the load-bearing wall, and dismantle the brick-concrete wall connecting the balcony;

4. Damage the original energy-saving facilities of the house and reduce the energy-saving effect;

5. Other behaviors that affect the safety of building structure and use.

Baidu Encyclopedia-Measures for the Administration of Residential Interior Decoration

Baidu Encyclopedia-Legal Responsibility of Property Management