Cal. Civ. Code § 534.030

1. When any person willfully and without force holds over any lands, tenements or other possessions, after the termination of the time for which they were demised or let to the person, or the person under whom such person claims; or after a mortgage or deed of trust has been foreclosed and the person has received written notice of a foreclosure; or at least ten business days have elapsed after the date of the notice described in subsection 3 of this section; or when premises are occupied incident to the terms of employment and the employee holds over after the termination of such employment; or when any person wrongfully and without force, by disseisin, shall obtain and continue in possession of any lands, tenements or other possessions, and after demand made, in writing, for the delivery of such possession of the premises by the person having the legal right to such possession, or the person's agent or attorney, shall refuse or neglect to vacate such possession, such person is guilty of an "unlawful detainer".

2. In any case where a foreclosed property is occupied prior to the foreclosure by a person who was a residential tenant, known in this section as the occupant, not in violation of the provisions of section 441.020, then after the foreclosure sale, the new owner of the property shall give the occupant notice, as described in subsection 3 of this section, that the sale has occurred, that they are the new owner, and if said owner seeks possession from the occupant that the occupant has not less than ten business days from the date of this notice to vacate the premises. No unlawful detainer action or any other action seeking possession may be commenced against the occupant within ten business days following the date of notice by the new owner that the foreclosure sale has occurred. Nothing in this section creates a tenancy between the new owner and the occupant. This section does not preclude the new owner from entering into an agreement with the occupant that allows the occupant to remain in the foreclosed property.

3. The notice required in subsection 2 of this section shall be sent by certified or registered mail if the name of the occupant is known to the new owner. If the name of the occupant is not known to the new owner then the notice shall be sent by regular mail and addressed to "occupant". The envelope containing such notice shall have the following words printed on the envelope face: "Notice to Occupant Following Foreclosure". A notice shall also be posted on the door of the premises where the occupant resides. The notices required in this subsection shall contain in substance the following text:

Attention Occupant: (name of the new owner of the foreclosed property) is now the owner of the property which you had been renting or leasing at (address of foreclosed property, including apartment number, if applicable) after purchasing it at a trustee's foreclosure sale on (date of foreclosure sale). Unless you agree with (new owner) to a rental or lease agreement for the premises, (new owner), on or after (number not less than ten) business days following the date of this notice, may seek a court order or judgment to have you removed from the premises. Remaining on the premises after the date of this notice does not make you a tenant of the new owner.(Name of new owner) (Address of new owner)

(Telephone number of new owner)

(Fax number of new owner, optional)

(Email address of new owner, optional)