Cal. Pub. Util. Code § 90793

Upon the hearing the board shall determine whether or not the agreement will be carried into execution and shall hear and determine all objections thereto. Failure of any person interested in the district or in the matter of the proposed execution of the agreement to show cause in writing pursuant to Section 90792 constitutes an assent on his part to a change in the boundaries of the district and to the execution of the agreement.