D.C. Code § 47-1202
The Mayor of the District of Columbia is authorized, but not directed, whenever in his judgment and discretion any property upon which a special assessment has been levied by the District of Columbia is not benefited by the improvement for which such special assessment was levied, or is benefited less than the amount of such assessment, or is unequally or inequitably assessed with relation to other property abutting such improvement, to abate, reduce, or adjust such assessment in accordance with such finding. This section shall not apply to any assessment levied by a jury in a condemnation proceeding, or to any assessment levied for work completed subsequent to June 25, 1938, or to any assessment levied under subchapter III of Chapter 4 of Title 9; provided, however, that nothing in this section shall be construed as affecting protests filed under the provisions of subchapter III of Chapter 4 of Title 9 within the time prescribed in said sections.
D.C. Code § 47-1202