D.C. Mun. Regs. tit. 24, r. 24-609
In all areas other than those zoned only for residential use, each licensee shall place and maintain a legible and conspicuous sign that is clearly visible at every entrance to the licensed premises. Each sign shall state the name of the licensee and the hours of the day and night during which the premises are open and attended for the storage of vehicles; and it shall comply with all applicable regulations in force in the District of Columbia.
Each sign shall also state, in a clearly visible manner, the hourly and daily rates charged for the storage of vehicles on the paid premises.
No licensee shall charge, or permit to be charged, any greater fee than is posted at the time of entry. Rates applicable to weekly or monthly contracts, however, need not be posted.
The provisions of this section shall also apply to parking facilities located in residential zones, except that each sign shall conform to the sign regulations applicable to residential zones.
D.C. Mun. Regs. tit. 24, r. 24-609