California Code, Government Code - GOV § 4304

Every contract for the construction, alteration or repair of public works or for the purchase of materials for public use shall contain a provision that only unmanufactured materials produced in the United States, and only manufactured materials manufactured in the United States, substantially all from materials produced in the United States shall be used in the performance of the contract.

Any person who fails to comply with such provision shall not be awarded any contract to which this article applies for a period of three years from the date of the violation.