The answer to your question is: it depends. Repairs need to be made within a reasonable amount of time. Each issue will have its own reasonable limits (and they are all pretty arbitrary). For example, I would expect the lack of a cooking source to be repaired within 24-48 hours, a leaking roof may take longer due to weather issues.
If your landlord has not responded to your request, then you must carefully document the issues. Write the landlord and explain each habitability issue. Request repairs be completed within a reasonable time. Keep a copy of your letter and make sure it is dated. If repairs are not completed, write again and let the landlord know you will be withholding rent until they are done, and that you expect your rent amount to be pro-rated based upon the uninhabitable issues. (You also have the option of having the repairs completed yourself and then deducting the repair cost from your rent).
You will need to put aside your full rental amount - the landlord will expect it. There is no set rule for apportioning the rent amount owed (and it may not even happen absent a court order) so be prepared to pay it all if you do not want to risk your tenancy.
You can also call the building inspector to inspect the unit and demand action.
I agree with Attorney Farley. The landlord has a "reasonable" time to effectuate repairs, but if the dwelling is totally uninhabitable, you have the right to withhold rent. Generally speaking, it is not wise to withhold rent without the advice of counsel. But for general information on this topic, see:
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.