California Code, Health and Safety Code - HSC § 26141

(a) Subject to subdivisions (c), (d), and (e), commercial and industrial landlords shall provide written disclosure to prospective and current tenants of the affected units as specified in subdivision (b), when the landlord knows that mold, both visible and invisible or hidden, is present that affects the unit or the building and the mold either exceeds the permissible exposure limits to molds established by subdivisions (a) and (b) of Section 26103 or poses a health threat according to the department's guidelines as developed pursuant to Section 26105.

(b) The written notice required by subdivision (a) shall be provided:

(c) A commercial and industrial landlord shall be exempt from providing written disclosure to prospective tenants pursuant to this section if the presence of mold was remediated according to the mold remediation guidelines developed by the department pursuant to Section 26130.

(d) A commercial or industrial landlord shall not be required to conduct air or surface tests of units or buildings to determine whether the presence of molds exceeds the permissible exposure limits to molds established by subdivisions (a) and (b) of Section 26103.

(e) The requirements of this section shall not apply until the first January 1 or July 1 that occurs at least six months after the department adopts standards pursuant to Sections 26103 and 26105 and develops guidelines pursuant to Section 26130.