Cal. Health and Safety Code § 26146

(a) A public entity that owns, leases, or operates a building shall provide written disclosure to all building occupants and prospective tenants as specified in subdivision (b) when the public entity knows, or has reasonable cause to believe, that a condition of chronic water intrusion or flood exists, or that mold, both visible and invisible or hidden, is present that affects the building or unit 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 developed pursuant to Section 26105. (b) The written notice required by subdivision (a) shall be provided: (1) To prospective tenants as soon as practicable and prior to entering into the rental agreement. (2) To current building occupants in affected units or buildings as soon as is reasonably practical. (c) A public entity shall be exempt from providing written disclosure to prospective tenants pursuant to subdivision (a) if the presence of mold was remediated according to the mold remediation guidelines developed by the department pursuant to Section 26130. (d) 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.