D.C. Mun. Regs. tit. 19, r. 19-1035
A vessel that is propelled by internal combustion engines shall be equipped with mufflers constructed and maintained to prevent any unnecessary, intense, or prolonged noise in the operation or management of the vessel.
Mufflers shall not be removed or rendered inoperative for any purpose whatsoever; provided, that during regattas, races, or similar events subject to regulation under § 1039 of this chapter, a participating vessel shall be exempt from the requirements of this section.
Nothing contained in this section shall apply to vessels equipped with underwater exhaust systems, or to vessels discharging water through open exhaust pipes, so long as these methods of silencing the exhaust are effective.
It shall be unlawful for any person to use any horn, bell, siren, or compression or exhaust whistle upon any vessel in District of Columbia waters, except as follows:
Owners or operators of vessels using District of Columbia waters shall not operate generators, pumps, or other noisemaking devices so as to create a nuisance.
D.C. Mun. Regs. tit. 19, r. 19-1035