Md. Code, Land Use § 20–603

(a) (1) A proposal for annexation of an area to the regional district shall be initiated by a written petition.

(2) The written petition shall be signed by:

(i) at least 25% of the residents of the area to be annexed who are registered as voters in county elections; and

(ii) owners of at least 25% of the assessed valuation of the real property located in the area to be annexed.

(b) If a written petition for annexation is submitted to the County Council, the chair of the County Council shall verify:

(1) the signatures on the written petition; and

(2) that the petition meets the requirements of subsection (a)(2) of this section.