Md. Code, Tax-Prop. § 8-402

(a) (1) The notice required by § 8–401 of this subtitle shall be served on the owner or other appropriate person: (i) by leaving a copy of the notice at the person’s residence; (ii) by sending a copy of the notice by United States mail to the mailing address of the owner; (iii) by personal service by the sheriff in the same manner as original service is required in a civil action; (iv) by e–mail, if within the past 3 years the recipient has provided to the Department an e–mail address and requested to receive the notices by e–mail; or (v) if the owner is unknown, not residing at the real property, or cannot be found by: 1. delivering a copy of the notice to a person in possession of the real property; or 2. posting a copy of the notice at a conspicuous location on the real property. (2) Though not a condition precedent to the validity of the value in the notice, if the mailing or e–mail address of an owner not residing at the real property is known, the notice shall be sent to that address. (b) If a notice is sent under this section, the supervisor shall retain a record of the date of sending and the name and address of the person to whom the notice is sent. (c) If the service under subsection (a) of this section is given to the person charged with paying the property tax, this section is deemed complied with even if that person is accountable to shareholders or other persons.