D.C. Code § 2-135
The Council of the District of Columbia and its successors are authorized and empowered to make and modify, and the Mayor of the District of Columbia and his successors are authorized and empowered to enforce, regulations governing plumbing, house drainage, and the ventilation, preservation, and maintenance in good order of house sewers and public sewers in the District of Columbia, and also regulations governing the examination, registration, and licensing of plumbers and the practice of the business of plumbing and gas-fitting in said District; and any person who shall neglect or refuse to comply with the requirements of the provisions of said regulations after 10 days notice of the specific thing required to be done thereunder, within the time limited by the Mayor for doing such work, or as the said time may be extended by said Mayor, shall upon conviction thereof be punishable by a fine of not more than $200 for each and every such offense, or in default of payment of fine, to imprisonment not to exceed 30 days. Civil fines, penalties, and fees may be imposed as alternative sanctions for any infraction of the regulations pursuant to Chapter 18 of Title 2. Adjudication of any infraction shall be pursuant to Chapter 18 of Title 2.
D.C. Code § 2-135
Building restrictions and regulations, zoning regulations, see § 6-641.01 et seq. .