(a) If real property is located partially outside and partially inside a taxing unit's boundaries, the portion inside the unit's boundaries shall be listed separately from the remaining portion.
(b) If real property is located partially inside the boundaries of more than one appraisal district, the chief appraisers who are responsible for appraising the property shall to the greatest extent practicable coordinate their appraisals of each portion of the property to ensure to the greatest extent possible that the property as a whole is appraised at its market value.
Official text of the Texas Tax Code as published by the Texas Legislative Council.