Cal. Government Code § 66326

(a) A local agency shall submit a copy of the ordinance adopted pursuant to Section 66314 to the Department of Housing and Community Development within 60 days after adoption. After adoption of an ordinance, the department may submit written findings to the local agency as to whether the ordinance complies with this article. (b) (1) If the department finds that the local agency’s ordinance does not comply with this article, the department shall notify the local agency and shall provide the local agency with a reasonable time, no longer than 30 days, to respond to the findings before taking any other action authorized by this article. (2) The local agency shall consider the findings made by the department pursuant to paragraph (1) and shall do one of the following: (A) Amend the ordinance to comply with this article. (B) Adopt the ordinance without changes. The local agency shall include findings in its resolution adopting the ordinance that explain the reasons the local agency believes that the ordinance complies with this article despite the findings of the department. (c) (1) If the local agency does not amend its ordinance in response to the department’s findings or does not adopt a resolution with findings explaining the reason the ordinance complies with this article and addressing the department’s findings, the department shall notify the local agency and may notify the Attorney General that the local agency is in violation of state law. (2) Before notifying the Attorney General that the local agency is in violation of state law, the department may consider whether a local agency adopted an ordinance in compliance with this article between January 1, 2017, and January 1, 2020. (d) If a local agency fails to submit a copy of its ordinance to the department within 60 days of adoption pursuant to this section or fails to respond to the department’s findings that the local ordinance does not comply with this article within 30 days pursuant to this section, that ordinance shall be null and void. The local agency shall thereafter apply the standards established in this article for the approval of accessory dwelling units, unless and until the agency adopts an ordinance that complies with this article, including, but not limited to, the submittal requirements of this section.