D.C. Code § 9-1209.01
The services of draftsmen, assistant engineers, levelers, transitmen, rodmen, chainmen, computers, copyists, overseers, and inspectors temporarily required in connection with sewer, water, street, street-cleaning, or road work, or construction and repair of buildings and bridges, or any general or special engineering or construction work authorized by appropriations may be employed exclusively to carry into effect District of Columbia appropriations when ordered by the Mayor of the District of Columbia in writing, and all such necessary expenditures for the proper execution of said work shall be paid from and equitably charged against the sums appropriated for said work; and the Mayor in his budget estimates shall report the number of such employees performing such services, and their work, and the sums paid to each, and out of what appropriation; provided, that the expenditures hereunder shall not exceed $42,000 during any 1 fiscal year; provided further, that, excluding Inspectors in the Sewer Department, 1 inspector in the Electrical Department, and 1 Inspector in the Repair Shop, no person shall be employed in pursuance of the authority contained in this section for a longer period than 9 months in the aggregate during any 1 fiscal year.
D.C. Code § 9-1209.01