California Code, Government Code - GOV § 815.4

A public entity is liable for injury proximately caused by a tortious act or omission of an independent contractor of the public entity to the same extent that the public entity would be subject to such liability if it were a private person. Nothing in this section subjects a public entity to liability for the act or omission of an independent contractor if the public entity would not have been liable for the injury had the act or omission been that of an employee of the public entity.