Legal Question in Landlord & Tenant Law in California

It is not against the law for the landlord to ASK, but the applicable code section does not give a landlord the RIGHT to enter for a "routine inspection". A tenant may want to consider allowing access anyway; among other things, a denial of entry will make it harder for to hold the landlord accountable for failing to prevent problems which could be revealed during such an inspection.

I agree with Mr. Dorfman and would add that if the tenant refuses entry for a routine inspection at reasonable intervals, usually annually, the tenant can be held for any deterioration or other conditions that the tenant fails to report and that then lead to costly repairs which might have been avoided had the problem been caught early. In short, there is simply zero up-side to denying the landlord reasonable periodic access to check the condition of the unit.