Okla. Admin. Code § 165:5-7-51 – Applications affecting public utility rates

(a) In utility rate cases where a general rate increase is sought, the applicant shall make a good faith effort to serve notice of the proposed rate change by mailing notice to all affected utility customers, unless the Commission directs otherwise. The notice shall:
1. (1) Contain information concerning the nature of the proposed changes and the effect of the changes on customer billing.
2. (2) Give the date and location of the hearing to be held. This notice may be included in regular customer billings but in any case shall be served at least fifteen (15) days prior to the date of hearing. A customer entitled to such a notice shall not be a respondent within the definition of 165:5-1-3 unless such customer enters an appearance in the cause pursuant to 165:5-13-3(c).
(b) Notice of hearing of an application for approval of any schedule, rate, charge, classification, rule or regulation which will directly or indirectly alter charges made for service performed, shall be published once each week for two (2) consecutive weeks at least fifteen (15) days prior to hearing in a newspaper of general circulation published in each county in which are located utility customers affected thereby, unless the Commission directs otherwise.