Maryland Code, Environment § 2-608

(a) Within 1 year after the Department issues a show-cause order or a corrective order, the Department shall take final action and attempt to secure compliance with any final order. If the Department has not secured compliance within this period, the Department shall take immediate steps to seek enforcement under § 2-609 of this subtitle.

(b) Nothing in this section prohibits the Department from bringing an action under § 2-609 of this subtitle within 1 year after the Department issues a show-cause order or a corrective order under this subtitle.