The employer of an inmate who is released from custody under a work release program shall pay the inmate’s wages direct to the city finance department. The mayor of the city may adopt regulations concerning the manner of disbursing any earnings of the inmates involved in the work release program. The mayor is authorized to withhold from an inmate’s wages the costs incident to the inmate’s confinement as the mayor shall deem appropriate and reasonable, provided however, that in no event shall the mayor withhold more than 20 percent of such inmate’s gross wages as the costs incident to such inmate’s confinement. After the costs incident to the inmate’s confinement have been deducted from the inmate’s earnings, the remainder of the inmate’s earnings shall be credited to the inmate’s account with the city finance department, and upon his release from confinement shall be turned over to the inmate. The mayor is authorized, however, to pay the balance of the inmate’s earnings to his family to be used by them for their support while the inmate is confined, provided the inmate has consented to such payment.