D.C. Code § 47-817

In establishing a real property tax rate or rates, the Council shall make a comparison of tax rates and burdens applicable to residential and nonresidential property in the District with those such rates applicable to such property in jurisdictions in the vicinity of the District. The comparison shall include other major taxes in addition to the tax on real property. Without in any way limiting the authority of the Council, it is the intention of Congress, that tax burdens in the District be reasonably comparable to those in the surrounding jurisdictions of the Washington metropolitan area.