Md. Code, Land Use § 16–309

(a) The Commission and the exclusive representative shall execute a collective bargaining agreement incorporating all matters agreed.

(b) A collective bargaining agreement may include a provision for:

(1) dues and maintenance or service fees paid by payroll deduction; and

(2) the arbitration of grievances arising under the collective bargaining agreement.

(c) The collective bargaining agreement supersedes any conflicting rule, regulation, or administrative policy of the Commission.