Oregon Revised Statutes Water Resources: Irrigation, Drainage, Flood Control, Reclamation § 548.910

(1) Each person signing a petition shall add after the signature of the person the date of signing and place of residence, giving street and number or a designation sufficient to enable the place of residence to be readily ascertained, and the number of acres of land owned by the signer. The name of the county whose assessment roll is used for the purpose of determining the right of the signer to vote shall be stated in the body of the petition or indicated opposite the signature of the signer. If the signer is a legal representative of the owner, the signature of the signer shall be accompanied by a certified copy of the authority of the signer to sign as a legal representative.

(2) After a petition has been offered for filing, a person may not withdraw the name of the person therefrom.

(3) A petition may designate not more than three persons as chief petitioners, setting forth their names and mailing addresses. A petition may consist of a single instrument or separate counterparts.