Maryland Code, Public Utilities § 25-106

(b)(1) A person may file a written claim with the Commission, in a form and containing the information and supporting documents required by the Commission, for a refund of the amount of a fee or charge the person paid to the Commission that exceeds the amount that is properly and legally payable.

(2) If the property for which the fee or charge was paid has been transferred to a new owner after the payment, the new owner may file the claim for the refund.

(c)(1) On the receipt of a claim for a refund under subsection (b) of this section, the Commission shall investigate the merits of the claim.

(2) On the request of the claimant, the Commission, or the Commission's designee, shall hold a hearing on the claim.

(3) A claim shall be disallowed unless it is filed within 3 years after the date of the payment for which the refund is requested.

(4) The Commission shall pay interest on any amount refunded under this section, calculated at the rate of 6% per year, starting 180 days from the date the claim was made.