Oregon Revised Statutes Public Health and Safety § 451.500

The district may by order or by ordinance, for the purpose of paying the costs of operation and maintenance of service facilities, and for the repayment of bonds, impose user charges on property served by the service facilities. The district may, from time to time when necessary, use moneys from the revolving fund for such maintenance and operation on a reimbursable basis. User charges, connection fees or service charges shall be based upon the costs of operation, maintenance and supervision of service facilities and the costs of bond repayment.