D.C. Mun. Regs. tit. 9, r. 9-467
Charges for room service and other service charges in connection with the serving of food or beverages (including alcoholic beverages) in hotels, motels, inns, cafes, bars, and similar establishments where food or drink are served shall be subject to tax under § 116 of the Act.
Cover, minimum, entertainment, or service charges, whether collected at the door of the establishment or added to the check, shall be taxable at the same rate as the food, drink, and alcoholic beverages served for consumption on the premises.
If a fixed percentage of the guest check representing gratuities or tips is added to charges for meals and drinks, and the purchaser is afforded no discretion with respect to the amount or method of payment, this charge is subject to the tax even though all or a part of the charge is paid by the vendor to the employees.
A gratuity or tip is not subject to tax (even though it may be charged to the customer's regular or credit card account and not paid directly to the server, waiter, or waitress at the time of sale or service) if both of the following conditions apply:
D.C. Mun. Regs. tit. 9, r. 9-467