(1) Sales study data. The basis of the real property ratio study is data obtained from real estate excise tax affidavits from each county. The department will supplement the sales study with appraisals when it is determined that the sales are insufficient to represent the level of assessment. The appraisals will be selected according to criteria set forth in WAC 458-53-130.

(2) Time period for data used. The sales study will only use sales occurring in the twelve-month period between May 1st preceding January of the current assessment year and April 30th of the current assessment year.

(3) Deduction from sale price. One percent will be deducted from the sale price shown on all valid real estate excise tax affidavits as an adjustment for values transferred that are not assessable as real property.

(4) Sales not included in the study - Assessment rolls using other than market value - New construction. Individual sales that show a sale price to assessed value ratio of under twenty-five percent, or over one hundred seventy-five percent shall be excluded from consideration in the study. However, if the number of individual sales meeting either one of these criteria exceeds five percent of the total number of valid sales for a county, then these sales shall be considered in the sales study.

(a) The exclusion of valid sales in accordance with this subsection shall not apply in situations where other than market value of a particular type of property is being listed on the assessment rolls of the county, as disclosed in any examination by the department. If other than market value is being listed on the assessment rolls for a particular type of real or personal property and, after notification by the department, is not corrected, the department shall adjust the ratio of that type of property, which adjustment shall be used in determining the county's indicated personal or real property ratio. When a particular type of property is found to be at other than market value, that type of property shall be separated from the other properties in the computation of the ratio. The department shall compile the total assessed value and total market value for that type of property, and it shall be included in the ratio as provided in WAC 458-53-135(3) and 458-53-160(3).

(b) The exclusion of valid sales in accordance with this subsection shall not apply to sales of property on which there is new construction value that has not yet been placed on the county assessment roll.