Cal. CCP § 1281.95

(a) In a binding arbitration of any claim for more than three thousand dollars ($3,000) pursuant to a contract for the construction or improvement of residential property consisting of one to four units, the arbitrator shall, within 10 days following his or her appointment, provide to each party a written declaration under penalty of perjury. This declaration shall disclose (1) whether the arbitrator or his or her employer or arbitration service had or has a personal or professional affiliation with either party, and (2) whether the arbitrator or his or her employer or arbitration service has been selected or designated as an arbitrator by either party in another transaction.

(b) If the arbitrator discloses an affiliation with either party, discloses that the arbitrator has been selected or designated as an arbitrator by either party in another arbitration, or fails to comply with this section, he or she may be disqualified from the arbitration by either party.

(c) A notice of disqualification shall be served within 15 days after the arbitrator makes the required disclosures or fails to comply. The right of a party to disqualify an arbitrator shall be waived if the party fails to serve the notice of disqualification pursuant to this subdivision unless the arbitration makes a material omission or material misrepresentation in his or her disclosure. Nothing in this section shall limit the right of a party to vacate an award pursuant to Section 1286.2, or to disqualify an arbitrator pursuant to any other law or statute.