D.C. Mun. Regs. tit. 29, § 1706
1706.1 The Department shall return to the obligor any overpayment of support submitted to the Department within thirty (30) workings days of receipt of written notice and sufficient documentation of an alleged overpayment.
1706.2 The overpayment refund shall be sent by mail to the obligor's last known address.
SOURCE: Final Rulemaking published at 35 DCR 2756, 2758 (April 15, 1988).