1. In making assessments of real property as required by the provisions of section 137.115, and in order to provide for the renovation of obsolete properties as authorized by § 7 of Article X of the Missouri Constitution, the county assessor shall not, for a period of five years after a deferred maintenance activity has been begun, add to the assessed value of a dwelling consisting of any number of residential units, regardless of the classification of the real property for assessment purposes, any additional assessed value because of deferred maintenance which has been begun upon such property during the period prescribed in section 137.113; except that, before any county assessor shall refrain from adding additional assessed valuation because of a deferred maintenance activity he shall determine that the property in question is on the tax rolls of the county and that no delinquent taxes on such property are due.

2. To be eligible for the tax relief afforded by subsection 1 of this section, a dwelling must be located on real property within an area satisfying the description set forth in § 7 of Article X of the Missouri Constitution. The governing body of each unit of local government of this state shall designate such areas within its boundaries by resolution, order, or ordinance, and each such resolution, order, or ordinance shall indicate the length of time the designation is to exist. Within thirty days of the date such resolution, order, or ordinance is passed, the unit of local government shall provide the assessor of the county or the city not within a county in which the designated area lies, a certified copy of the resolution, order, or ordinance designating the area and a map of the area so designated clearly showing the boundaries of the area, as well as all the streets lying within the area. Each unit of local government which designates an area for the tax relief set forth in subsection 1 of this section shall establish a procedure whereby any person may apply to the unit of local government, or an agency thereof, for certification that a designated dwelling lies within an area duly designated for such tax relief. This certification shall also specify the items of deferred maintenance completed on the dwelling. Within twenty days after the issuance of such a certificate, the unit of local government shall transmit to the assessor of the county or city not within a county in which the real property lies a copy of the certificate. Upon receipt of such certificate, the assessor shall determine whether the property in question is eligible for the assessment postponement provided for in subsection 1 of this section and shall issue to the owner of the real property a formal declaration of whether such tax relief is to be made available, and, if so, also indicating the assessed valuation of the real property immediately prior to the deferred maintenance and the term of the assessment postponement. As used in this subsection, the phrase “unit of local government” shall mean the municipality within whose boundaries the area to be designated lies. If the area does not lie within the boundaries of any municipality, then “unit of local government” shall mean the county within whose boundaries the area to be designated lies.