Cal. Health & Safety Code § 19300
(a) This chapter applies to all of the following structures, as defined in Chapter 3 (commencing with Section 301.1) of Part 2, the California Building Code, of Title 24, the California Building Standards Code, of the California Code of Regulations, that are constructed on or after January 1, 2017, or are constructed prior to January 1, 2017, and modified, renovated, or tenant improved, as described in subdivision (b), subsequent to that date:
(b) A structure shall be considered modified, renovated, or tenant improved for purposes of subdivision (a) if the structure is subject to any of the following on or after January 1, 2020:
(d)