Delaware constitution
Article VIII
Section 7

In all assessments of the value of real estate for taxation, the value of the land and the value of the buildings and improvements thereon shall be included. And in all assessments of the rental value of real estate for taxation, the rental value of the land and the rental value of the buildings and the improvements thereon shall be included. The foregoing provisions of this section shall apply to all assessments of the value of real estate or of the rental value thereof for taxation for State, county, hundred, school, municipal or other public purposes.