WAC 480-70-251
WAC 480-70-251. Tariffs, rates and charges, general
(1) Rates and charges must cover a complete service, including disposal, unless a separate charge for disposal is specifically named in the tariff.
(2) Rates and charges must be stated by unit and billing method. For example: Dollars and cents per can, per trip, per hour, per service, per week, per month, or other.