Maryland Code, Tax-Property § 7-108

(a) The governing body of a county may reduce, by law, the percent of the assessment of any personal property that is subject to the county property tax under § 7-222 or § 7-225 of this title.

(b) A county that reduces or eliminates the percent of assessment of taxable personal property under subsection (a) of this section shall submit a copy of the law to the Department. If the Department receives a copy of the law on or before May 1, the change shall be effective for the taxable year following the date the law is enacted.