Cal. Health and Safety Code § 26142

(a) Any tenant of a commercial or industrial real property who knows that mold is present in the building, heating system, ventilating or air-conditioning system, or appurtenant structures, or that there is a condition of chronic water intrusion or flood, shall inform the landlord of this knowledge in writing within a reasonable period of time. The tenant shall make the property available to the landlord or his or her agents for appropriate assessment or remedial action as soon as is reasonably practicable if the landlord is responsible for maintenance of the property. Nothing in this section is intended to any way affect existing duties and obligations of residential tenants and landlords. (b) 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.