Cal. Business and Professions Code § 21703

If any part of the rent or other charges due from an occupant remain unpaid for 14 consecutive days, an owner may terminate the right of the occupant to the use of the storage space at a self-service storage facility by sending a notice to the occupant’s last known address and to the alternative address specified in subdivision (b) of Section 21712. The notice shall be sent by certified mail, postage prepaid, by regular first-class mail if the owner obtains a certificate of mailing indicating the date the notice was mailed, or by email pursuant to subdivision (c) of Section 21712. The notice shall contain all of the following: (a) An itemized statement of the owner’s claim showing the sums due at the time of the notice and the date when the sums became due. (b) A statement that the occupant’s right to use the storage space will terminate on a specified date (not less than 14 days after the mailing of the notice) unless all sums due are paid by the occupant before the specified date. (c) A notice that the occupant may be denied access to the storage space after the termination date if the sums are not paid and that an owner’s lien, as provided for in Section 21702, may be imposed thereafter. (d) The name, street address, and telephone number of the owner or their designated agent whom the occupant may contact to respond to the notice.