Cal. Government Code § 65584.09

(a) For housing elements due pursuant to Section 65588 on or after January 1, 2006, if a city or county in the prior planning period failed to identify or make available adequate sites to accommodate that portion of the regional housing need allocated pursuant to Section 65584, then the city or county shall, within the first year of the planning period of the new housing element, zone or rezone adequate sites to accommodate the unaccommodated portion of the regional housing need allocation from the prior planning period. (b) The requirements under subdivision (a) shall be in addition to any zoning or rezoning required to accommodate the jurisdiction’s share of the regional housing need pursuant to Section 65584 for the new planning period. (c) Nothing in this section shall be construed to diminish the requirement of a city or county to accommodate its share of the regional housing need for each income level during the planning period set forth in Section 65588, including the obligations to (1) implement programs included pursuant to Section 65583 to achieve the goals and objectives, including programs to zone or rezone land, and (2) timely adopt a housing element with an inventory described in paragraph (3) of subdivision (a) of Section 65583 and a program to make sites available pursuant to paragraph (1) of subdivision (c) of Section 65583, which can accommodate the jurisdiction’s share of the regional housing need.