Although Civil Code section 1954 covers the general topic of when a landlord can enter a rental dwelling, there is no specific answer under California law to your extremely fact-specific situation. You will just need to work out with your landlord how and when the shared bathroom will be shown to prospective tenants.
Frank W. Chen has been licensed to practice law in California since 1988. The information presented here is general in nature and is not intended, nor should be construed, as legal advice for a particular case. This Avvo.com posting does not create any attorney-client relationship with the author. For specific advice about your particular situation, please consult with your own attorney.