(1) Water companies must use the uniform system of accounts (USOA) published by the National Association of Regulatory Utility Commissioners (NARUC). Information about the USOA regarding the version adopted and where to obtain it is set out in WAC 480-110-999 (Adoption by reference). The USOA sets out the accounting requirements for Class A, B, and C water companies.

Water companies are classified by revenues.

(2) A water company may use the accounting requirements for a higher class if it chooses.

(3) The commission will distribute an annual report form that each water company must complete and file with the commission for the prior calendar year. The annual report must be filed, and the company's regulatory fee paid, no later than May 1 of each year.

(4) A written request for the extension of the time for filing the annual report can be made prior to May 1. The commission does not grant an extension of time for payment of regulatory fees.

(5) The maximum water company regulatory fee is set by statute at one-tenth of one percent of the first fifty thousand dollars of gross intrastate operating revenue plus two-tenths of one percent of any gross operating revenue in excess of fifty thousand dollars.

(a) The maximum regulatory fee is assessed each year, unless the commission issues an order establishing the regulatory fee at an amount less than the statutory maximum.

(b) The minimum regulatory fee that a water company must pay is twenty dollars.

(c) The twenty-dollar minimum regulatory fee is waived for any water company with less than twenty thousand dollars in gross intrastate operating revenue.

(d) The commission does not grant extensions for payment of regulatory fees.

(e) If a company does not pay its regulatory fee by May 1, the commission will assess an automatic late fee of two percent of the amount due, plus one percent interest for each month the fee remains unpaid.