Maryland Family Law Section 10-121
(a)   Any order under this Part III of this subtitle that is passed on or after July 1, 1985 shall constitute an immediate and continuing withholding order on all earnings of the obligor that are due on or after the date of the support order.
(b)   (1)   Any order under this Part III of this subtitle that is passed before July 1, 1985 shall become an immediate and continuing withholding order on all earnings of the obligor that are due on or after the date of the withholding order on the filing by the recipient or support enforcement agency of:
(i)   a motion for a withholding order on the earnings of the obligor; and
(ii)   a current support order.
(2)   Notice of the filing of the motion and a statement that the support order constitutes an earnings withholding order subject to the conditions of this Part III of this subtitle shall be sent to the obligor by certified mail, return receipt requested and first class mail, at the last known home address or, if the home address is unknown, the place of employment of the obligor.
(c)   Any support order or modification of support order not subject to immediate withholding under § 10-123 of this subtitle, that is passed on or after July 1, 1985, and any notice and statement issued under subsection (b)(2) of this section shall include a statement that:
(1)   if the obligor accumulates support payments arrears amounting to more than 30 days of support, the obligor shall be subject to earnings withholding;
(2)   the obligor is required to notify the court within 10 days of any change of address or employment so long as the support order is in effect; and
(3)   failure to comply with item (2) of this subsection will subject the obligor to a penalty not to exceed $250 and may result in the obligor's not receiving notice of proceedings for earnings withholding.