Md. Code Regs. 26.20.31.08
In most instances, notices of violation and cessation orders will be issued by a Bureau inspector immediately upon discovery of conditions warranting the action. The inspector will first attempt to serve the operator at the site of the violation. If the operator is not available, the inspector may serve any individual at the site who appears to be an employee or agent of the permit holder or operator. In all cases, service shall be complete upon tender of a notice or order, and is not deemed incomplete because of refusal to accept delivery. Service may also be effected by mailing a copy of the notice or order in writing, and by certified mail, to the last address the permittee has filed with the Bureau. Service on a person conducting an unpermitted operation may also be effected by certified mail. Service in this manner is complete upon mailing, and not considered incomplete because of refusal to accept delivery.
Md. Code Regs. 26.20.31.08