ORS 466.725: Limitation on local government regulation.

(1) Except as provided in ORS 466.730, a local unit of government may not enact or enforce any ordinance, rule or regulation relating to the matters encompassed by the state program established under ORS 466.720.

      (2) Any ordinance, rule or regulation enacted by a local unit of government of this state that encompasses the same matters as the state program shall be unenforceable, except for an ordinance, rule or regulation:

      (a) That requires an owner or permittee to report a release to the local unit of government; or

      (b) Adopted by a local unit of government operating an underground storage tank program pursuant to a contract entered into according to the provisions of ORS 466.730.