Md. Code, Environment § 2–603

(a) A show–cause order issued under this subtitle shall:

(1) Specify the provision that allegedly has been violated;

(2) Describe the nature and extent of the alleged violation;

(3) Require the person charged to appear at a hearing and show cause why an order requiring corrective action should not be issued; and

(4) State the date, time, and place of the hearing.

(b) Each show–cause order issued under this subtitle shall be in writing and shall be served:

(1) Not less than 20 days before the time set for the hearing; and

(2) As a summons is served under the Maryland Rules or by certified mail.