Md. Code, Land Use § 24–310

(a) (1) An agreement shall be recorded in the land records of Montgomery County.

(2) If an agreement is not recorded as required under paragraph (1) of this subsection within 20 days after its execution by all parties, the agreement is void.

(b) When an agreement is recorded under subsection (a) of this section, the parties to the agreement and their successors in interest are bound to the agreement.