Oregon Revised Statutes Property Rights and Transactions § 90.360

(1)(a) Except as provided in this chapter, if there is a material noncompliance by the landlord with the rental agreement or a noncompliance with ORS 90.320 or 90.730, the tenant may deliver a written notice to the landlord specifying the acts and omissions constituting the breach and that the rental agreement will terminate upon a date not less than 30 days after delivery of the notice if the breach is not remedied in seven days in the case of an essential service or 30 days in all other cases, and the rental agreement shall terminate as provided in the notice subject to paragraphs (b) and (c) of this subsection.  However, in the case of a week-to-week tenancy, the rental agreement will terminate upon a date not less than seven days after delivery of the notice if the breach is not remedied.

(b) If the breach is remediable by repairs, the payment of damages or otherwise and if the landlord adequately remedies the breach before the date specified in the notice, the rental agreement shall not terminate by reason of the breach.

(c) If substantially the same act or omission that constituted a prior noncompliance of which notice was given recurs within six months, the tenant may terminate the rental agreement upon at least 14 days' written notice specifying the breach and the date of termination of the rental agreement.  However, in the case of a week-to-week tenancy, the tenant may terminate the rental agreement upon at least seven days' written notice specifying the breach and date of termination of the rental agreement.

(a) The tenant knew or reasonably should have known of the condition and failed to give actual notice to the landlord in a reasonable time prior to the occurrence of the personal injury, damage to personal property, diminution in rental value or other tenant loss resulting from the noncompliance;  or

(b) The condition was caused after the tenancy began by the deliberate or negligent act or omission of someone other than the landlord or a person acting on behalf of the landlord.