The IPC, is not the code in CA.
In CA ,
California Residential Building Code 2022
R306.1 Toilet Facilities
Every dwelling unit shall be provided with a water closet, lavatory, and a bathtub or shower.
R306.2 Kitchen
Each dwelling unit shall be provided with a kitchen area and every kitchen area shall be provided with a sink
R306.3 Sewage Disposal
Plumbing fixtures shall be connected to a sanitary sewer or to an approved private sewage disposal system.
R306.4 Water Supply to Fixtures
Plumbing fixtures shall be connected to an approved water supply.
Kitchen sinks, lavatories, bathtubs, showers, bidets, laundry tubs and washing machine outlets shall be provided with hot and cold water.
CPC 713.0 Sewer Required.
713.1 Where Required. A building in which plumbing fixtures are installed and premises having drainage piping thereon shall have a connection to a public or private sewer, except as provided in Section 713.2, and Section 713.4.
713.2 Private Sewage Disposal System. Where no public sewer intended to serve a lot or premises is available in a thoroughfare or right of way abutting such lot or premises, drainage piping from a building or works shall be connected to an approved private sewage disposal system.
713.3 Public Sewer. Within the limits prescribed by Section
713.4 hereof, the rearrangement or subdivision into smaller parcels of a lot that abuts and is served by a public sewer shall not be deemed cause to permit the construction of a private sewage disposal system, and plumbing or drainage systems on a smaller parcel or parcels shall connect to the public sewer.
713.4 Public Sewer Availability. The public sewer shall be permitted to be considered as not being available where such public sewer or a building or an exterior drainage facility connected thereto is located more than 200 feet from a proposed building or exterior drainage facility on a lot or premises that abut and is served by such public sewer.
[HCD 1] For residential occupancies, the public sewer may be considered as not being available by the Authority Having Jurisdiction.
STATE OF CALIFORNIA • UNINHABITABLE CONDITIONS
Civil Code Sections 1941.1 and 1941.3, Health and Safety Code Section 13113.7, and Health and Safety Code Sections 17920-17928
A dwelling may be considered uninhabitable (unlivable) if it substantially lacks any of the following:
"......
• Plumbing facilities in good working order, including hot and cold running water furnished to appropriate fixtures, connected to a sewage disposal system.
In addition to these requirements, each rental unit must have all of the following:
• A working toilet, wash basin, and bathtub or shower. The toilet and bathtub or shower must be in a room, which is ventilated and allows privacy.
• A kitchen with a sink that cannot be made of an absorbent material such as wood. ....."