California Code, Public Utilities Code - PUC § 728.7

(1) Require the telephone corporation requesting authorization to increase subscriber rates or to impose a charge or surcharge on subscribers as a result of a change in the payments, to notify its subscribers, whenever the commission commences a proceeding on its own motion or in response to a petition to authorize a change in the amount of those payments or to impose that charge, surcharge, or rate increase as a result of a change in the amount of those payments.

(2) Require the telephone corporation to provide its subscribers with an exact description of, and explanation for, the change in the amount of the payment or the imposition of a charge, surcharge, or rate increase, within 90 days of the authorized change in the amount of payment or charge, surcharge, or rate increase.  The description and explanation shall include a reasonably accurate quantitative assessment of the results of, and the reasons for, the change in the amount of payment or imposition of a charge, surcharge, or rate increase for each class of subscriber.