California law states that a landlord can enter a rental unit only for the following reasons:
* In an emergency.
* When the tenant has moved out or has abandoned the rental unit.
* To make necessary or agreed-upon repairs, decorations, alterations, or other improvements.
* To show the rental unit to prospective tenants
, purchasers, or lenders, to provide entry to contractors or workers who are to perform work on the unit, or to conduct an initial inspection before the end of the tenancy (see Initial Inspection sidebar).
* If a court order permits the landlord to enter.87
* If the tenant has a waterbed, to inspect the installation of the waterbed when the installation has been completed, and periodically after that to assure that the installation meets the law's requirements.88 The landlord or the landlord's agent must give the tenant reasonable advance notice in writing before entering the unit, and can enter only during normal business hours (generally, 8 a.m. to 5 p.m. on weekdays).
The landlord or agent may use any one of the following methods to give the tenant written notice of intent to enter the unit. The landlord or agent may:
* Personally deliver the notice to the tenant; or
* Leave the notice at the rental unit with a person of suitable age and discretion (for example, a roommate or a teenage member of the tenant's household); or
* Leave the notice on, near or under the unit's usual entry door in such a way that it is likely to be found; or
* Mail the notice to the tenant.89
The law considers 24 hours' advance written notice to be reasonable in most situations.
If your landlord violates these access rules, talk to the landlord about your concerns. If that is not successful in stopping the landlordís misconduct, send the landlord a formal letter asking the landlord to strictly observe the access rules stated above. If the landlord continues to violate these rules, you can talk to an attorney or a legal aid organization, or file suit in small claims court to recover damages that you have suffered due to the landlordís misconduct. If the landlordís violation of these rules was significant and intentional, and the landlordís purpose was to influence you to move from the rental unit, you can sue the landlord in small claims court for a civil penalty of up to $2,000 for each violation.93b
<source and more info