Cal. Civ. Proc. Code § 410.42

(a) The following provisions of a contract between the contractor and a subcontractor with principal offices in this state, for the construction of a public or private work of improvement in this state, shall be void and unenforceable:
1. (1) A provision which purports to require any dispute between the parties to be litigated, arbitrated, or otherwise determined outside this state.
2. (2) A provision which purports to preclude a party from commencing such a proceeding or obtaining a judgment or other resolution in this state or the courts of this state.
(b) For purposes of this section, “construction” means any work or services performed on, or materials provided for, a work of improvement, as defined in Section 8050 of the Civil Code, and for which a lien may be claimed pursuant to Section 8400 of the Civil Code (whether or not a lien is in fact claimed) or for which such a lien could be claimed but for Section 8160 of the Civil Code.