Oregon Revised Statutes Mineral Resources § 523.110

Any district may adopt and promulgate regulations concerning the use of geothermal heat and the property of the district. The board of commissioners may refuse to supply any building, place or premises with geothermal heat where the user fails after 10 days' written notice to comply with the regulations. The written notice shall be by registered mail or by certified mail with return receipt and shall be deemed given when it is deposited in the United States Post Office properly addressed with postage prepaid.