The telephone service supplier shall bill its customers within the Kenosha County E911 emergency telephone system area in amounts sufficient to recover its nonrecurring and recurring charges, as provided in section 146.70(3), Wisconsin Statutes, and in the manner allowed by PSC rules, regulations and tariffs. The service supplier shall review access line and billable accounts at least every three years. This count shall be provided to the County. The line count shall be used as a basis for adjusting the monthly user rate. [Code § 18.01-5.]