California Code, Revenue and Taxation Code - RTC § 2910.7

Any person who receives a tax bill respecting property which has been assessed to another and who has power, pursuant to written or oral authorization, to pay the taxes on behalf of another shall after the taxes have been paid in full and within 30 days of the receipt of the written request of the assessee, either deposit the original or a copy of the bill in the United States mail in an envelope addressed to the last known address of the assessee as shown on the bill, postage being prepaid, or deliver it otherwise to the assessee within said 30 days.