Oregon Revised Statutes Cities § 224.510

(1) Unless prohibited by its charter, a city may impose on the users of water a sewage charge which shall be billed and collected by the city. The proceeds of the sewage charge may be used for paying, in whole or in part, the cost of planning, constructing or operating a sewage disposal system.

(2) The sewage charge shall be established and the rate fixed by the city's governing body.