(1) Introduction. When classified farm and agricultural or timber land is connected to a domestic water system, sewerage facilities, or road improvements, a partial special benefit assessment will be made. This section explains the manner in which this partial assessment is calculated.

(2) General obligation. A portion of the exempt classified farm and agricultural land shall be subject to special benefit assessment if it is actually connected to the domestic water system or sewerage facilities, or for access to a road improvement.

(3) Amount of partial assessment. The amount of special benefit assessment shall be calculated by the method used in the district to assess nonexempt property. If a district uses more than one method to calculate the assessment, it shall use the one that results in the least cost to the property owner, regardless of the owner's property holdings and/or exempt status. The district shall provide the owner of the property with a written estimate of the partial assessment as determined from the following methods:

(a) For assessments relating to sanitary and/or storm sewerage service or domestic water service one of the following methods shall be used:

(i) Square foot method: If the special benefit assessment is determined on a square footage basis, the assessable portion of the exempt land shall be determined as follows:

(A) Calculate the square footage of the residential area, i.e., the "main dwelling."

(B) This area shall include all those facilities normally found on a residential lot such as a garage or carport, driveway, front and back yards, etc. Also included in the area shall be any buildings or facilities directly benefited by an actual connection to the improvement. (For example: A dairy barn connected to a sewer or water system.)

(ii) Front foot method: If the special benefit assessment is determined on a front footage basis, the assessable portion of the exempt land shall be determined by one of the following:

(A) Calculate the square footage for the residential area in the same manner as the square foot method. The square foot measurement of the entire "residence," shall then be converted into the area of a square. The calculated square will be used as the unit to be charged for the special benefit assessment. One side of the square will be used as front footage; or

(B) Determine the mean (average) front footage of all nonexempt properties within the district, and use it to assess the portion of otherwise exempt property for the special benefit assessment, i.e., add all of the nonexempt front footage relevant to the improvement and divide by the number of nonexempt properties within the district.

(iii) Zone-termini method: If the special benefit assessment is determined on a zone-termini basis, the assessable portion of the exempt land shall be determined by one of the following:

(A) Convert the square foot area of the residence to a square as in the front foot method. Use this square as the zone for assessing the portion of otherwise exempt property for the special benefit assessment; or

(B) Calculate the mean (average) width and depth (length) of all nonexempt properties within the district, using these averages to create a rectangular unit as the zone for assessing the portion of otherwise exempt property for the special benefit assessment. To perform this calculation:

(I) Add all nonexempt front footage relevant to the improvement and divide by the number of nonexempt properties within the district to determine the mean width of the zone; and

(II) Add the depths (lengths) of all nonexempt properties within the district and divide by the number of nonexempt properties within the district to determine the mean depth of the zone.

(iv) Equivalent residential unit method (ERU): The ERU method shall be used in the same manner as it is used on all other properties within the district. The value to be determined is based on the amount of benefit derived or, when appropriate, the degree of contribution to the service, such as drainage or sewer. This amount shall be measured for all uses of property. (For example, if a dairy barn uses a greater amount of water or contributes a greater amount of sewerage than the normal residential unit, it shall be classified as more than one ERU and shall be charged a proportionately greater amount.)

(v) Combined methods: In districts making assessments using a combination of two or more methods (e.g., an assessment based on a front footage charge plus a square foot charge), the procedures for determining the assessable portion of previously exempt property shall be the same as those described above.

(b) For assessments relating to road construction and/or improvements. If the property is provided access to a constructed or improved road, the assessment will be based upon the percentage of current use value to true and fair value as evidenced by the last property tax assessment roll as equalized by the county board of equalization to what the assessment would have been if the owner had waived the exemption. (For example, if the current use value is forty-five percent of its true and fair value, then the assessable portion is forty-five percent of the amount the assessment would have been if the owner had waived the exemption.)