Cal. PEN § 629.60

Whenever an order authorizing an interception is entered, the order shall require reports in writing or otherwise to be made to the judge who issued the order showing the number of communications intercepted pursuant to the original order, and a statement setting forth what progress has been made toward achievement of the authorized objective, or a satisfactory explanation for its lack, and the need for continued interception. If the judge finds that progress has not been made, that the explanation for its lack is not satisfactory, or that no need exists for continued interception, he or she shall order that the interception immediately terminate. The reports shall be filed with the court at the intervals that the judge may require, but not less than one for each period of 10 days, commencing with the date of the signing of the order, and shall be made by any reasonable and reliable means, as determined by the judge.