Cal. Government Code § 4216.8

This article does not apply to any of the following persons: (a) An owner of real property who contracts for an excavation project on the property, not requiring a permit issued by a state or local agency, with a contractor or subcontractor licensed pursuant to Article 5 (commencing with Section 7065) of Chapter 9 of Division 3 of the Business and Professions Code. (b) An owner of residential real property, not engaged as a contractor or subcontractor licensed pursuant to Article 5 (commencing with Section 7065) of Chapter 9 of Division 3 of the Business and Professions Code, who as part of improving his or her principal residence or appurtenances thereto is performing or having performed excavation work not requiring a permit issued by a state or local agency. (c) Any person or private entity that leases or rents power operated or power-driven excavating or boring equipment, regardless of whether an equipment operator is provided for that piece of equipment or not, to a contractor or subcontractor licensed pursuant to Article 5 (commencing with Section 7065) of Chapter 9 of Division 3 of the Business and Professions Code, if the signed rental agreement between the person or private entity and the contractor or subcontractor contains the following provision: “It is the sole responsibility of the lessee or renter to follow the requirements of the regional notification center law pursuant to Article 2 (commencing with Section 4216) of Chapter 3.1 of Division 5 of Title 1 of the Government Code. By signing this contract, the lessee or renter accepts all liabilities and responsibilities contained in the regional notification center law.”