Maryland Code, PUBLIC UTILITIES 7-302
(2) The consumer is entitled to be present for the test.
(b) (1) The Commission shall set a percentage tolerance limit for the accuracy of an electric meter or gas meter.
(2) The Commission shall order a gas company or electric company to replace a meter at the company’s expense if the meter is incorrect to the prejudice of the consumer by more than the percentage tolerance limit set by the Commission.
(c) (1) The Commission shall set a uniform reasonable fee for meter test services under this section.
(2) (i) If the test indicates that the meter is within the percentage tolerance limit set by the Commission under subsection (b)(1) of this section, the consumer shall pay the test fee.
(ii) If the test indicates that the meter is not within the percentage tolerance limit set by the Commission, the Commission shall refund the fee.