2015 ORS 311.505
(1) Except as provided in subsection (6) of this section, the first one-third of all taxes and other charges due from the taxpayer or property, levied or imposed and charged on the latest tax roll, shall be paid on or before November 15, the second one-third on or before February 15, and the remaining one-third on or before May 15 next following.
(2) Interest shall be charged and collected on any taxes on property, other charges, and on any additional taxes or penalty imposed for disqualification of property for special assessment or exemption, or installment thereof not paid when due, at the rate of one and one-third percent per month, or fraction of a month until paid.
(3) Discounts shall be allowed on partial or full payments of such taxes, made on or before November 15 as follows:
(a) Two percent on two-thirds of such taxes so paid.
(b) Three percent where all of such taxes are so paid.
(4) For purposes of this section, "taxes" includes all taxes on property as defined in ORS 310.140 (Legislative findings) and certified to the assessor under ORS 310.060 (Notice certifying taxes) except taxes assessed on any other property which have by any means become a lien against the property for which the payment was made.
(5) All interest collected and all discounts allowed shall be prorated to the several municipal corporations, taxing districts and governmental agencies sharing in the taxes or assessments.
(6) If the total property tax is less than $40, no installment payment of taxes shall be allowed. [Amended by 1953 c.49 §2; 1957 c.543 §1; 1965 c.344 §26; 1973 c.142 §1; 1975 c.704 §2; 1979 c.241 §9; 1979 c.703 §§1, 3; 1987 c.529 §2; 1991 c.459 §252; 1997 c.819 §17; 1999 c.701 §1]