Cal. Code Civ. Proc. § 632
In superior courts, upon the trial of a question of fact by the court, written findings of fact and conclusions of law shall not be required. The court shall issue a statement of decision explaining the factual and legal basis for its decision as to each of the principal controverted issues at trial upon the request of any party appearing at the trial. The request must be made within 10 days after the court announces a tentative decision unless the trial is concluded within one calendar day or in less than eight hours over more than one day in which event the request must be made prior to the submission of the matter for decision. The request for a statement of decision shall specify those controverted issues as to which the party is requesting a statement of decision. After a party has requested the statement, any party may make proposals as to the content of the statement of decision.
The statement of decision shall be in writing, unless the parties appearing at trial agree otherwise; however, when the trial is concluded within one calendar day or in less than 8 hours over more than one day, the statement of decision may be made orally on the record in the presence of the parties.
Ca. Civ. Proc. Code § 632