(a) The recordation of a plan or plat, or the designation of proposed land use by a county or municipal planning authority, shall not be used by the assessor as a basis in the valuation or assessment of real property for the purposes of taxation, except as hereafter provided. The valuation of real property contained in a recorded plan or plat is as follows:

(1) When a lot or parcel within a recorded plan or plat is sold, that lot shall be revalued by the county assessor or Tax Commissioner. In no event may the remaining lots within the recorded plan or plat be automatically revalued solely based upon the sale of other lots within the recorded plan or plat.

(2) When land contained within a recorded plan or plat is first developed and actually used for a commercial, residential or industrial purpose, the land shall be revalued by the county assessor or the Tax Commissioner, depending upon whoever has authority over the land, but in no event may the remaining lots within the recorded plan or plat be automatically revalued solely based upon the sale of other lots within the recorded plan or plat.

(b) For valuation of the remaining lots or parcels or undeveloped portion within the recorded plan or plat, the following factors shall be taken into consideration in determining the valuation: (1) Availability of improved roads; (2) availability of sewage disposal and drinking water supply, including, but not limited to, the use of such factors as availability of public water and sewage systems, private water systems, water wells, private sewage and septic systems or potential private sewage and septic systems; (3) availability of electrical, telephone and other utility services; and (4) percentage of completion of improvements and infrastructure development. The assessor shall annually determine the percentage of completion of improvements and infrastructure development. The Tax Commissioner shall propose a legislative rule for submission to the Legislature pursuant to the provisions of article three, chapter twenty-nine-a of this code, which rule shall describe in detail the methodology and use of the factors set out above, as well as any other factors determined by the Tax Commissioner to be applicable, for valuation of percentage of completion of improvements and infrastructure development. The remaining lots or parcels or undeveloped portion within the recorded plan or plat are not managed timberland for purposes of valuation of management timberland under sections eleven and eleven-a, article one-c of this chapter. For purposes of classification of property for levy purposes under section five, article eight of this chapter, developed lots or parcels shall not be reclassified from Class III to Class II or from Class IV to Class II until the developed lot or parcel is used and occupied by the owner thereof exclusively for residential purposes as defined in section three, article four of this chapter.

(c) The designation of proposed land use by a county or municipal planning authority may not be used or considered by an assessor in determining the appraised value of property included under a designation of proposed land use by a county or municipal planning authority until such time as the actual use of the real property has changed to correspond to the proposed use. For purposes of this subsection, the actual use of real property shall be treated as having changed to correspond to the proposed use as improvements on the property necessary for the proposed use are completed: Provided, That in valuing the property before its change to actual use, the assessor may consider the factors described in subsection (b) of this section.

(d) The amendments made to this section by the Legislature in 2000 shall become effective on July 1, 2000, and shall be effective as to all plans or plats filed after June 30, 2000. The provisions of the amendments made to this section in 2000 do not apply to unsold lots or parcels or undeveloped land contained within recorded plans or plats which were recorded prior to July 1, 2000: Provided, That in no event may the appraised value of unsold lots or parcels or undeveloped land contained within these recorded plans or plats be less than their appraised value as of July 1, 2000.