29 CFR § 525.5 - Wage payments.

(a) An individual whose earning or productive capacity is not impaired for the work being performed cannot be employed under a certificate issued pursuant to this part and must be paid at least the applicable minimum wage. An individual whose earning or productive capacity is impaired to the extent that the individual is unable to earn at least the applicable minimum wage may be paid a commensurate wage, but only after the employer has obtained a certificate authorizing payment of special minimum wages from the appropriate office of the Wage and Hour Division of the Department of Labor.

(b) With respect to patient workers employed in institutions, no deductions can be made from such individuals' commensurate wages to cover the cost of room, board, or other services provided by the facility. Such an individual must receive his or her wages free and clear, except for amounts deducted for taxes assessed against the employee and any voluntary wage assignments directed by the employee. (See part 531 of this title.) However, it is not the intention of these regulations to preclude the institution thereafter from assessing or collecting charges for room, board, and other services actually provided to an individual to the extent permitted by applicable Federal or State law and on the same basis as it assesses and collects from nonworking patients.