Maryland Code, Local Government § 26-804

(a)(1) The board of managers may impose a special assessment on the public and private benefited land for maintenance of a drainage project constructed under this title.

(2) If the board of managers requests, the county commissioners or county council may appoint a board of viewers to evaluate changes in land use made after the original determination for a drainage project.

(3) The board of managers may use the evaluation report as a basis to impose a special assessment for maintenance of a drainage project.