D.C. Code § 2-110

There shall be paid to the Director of the Department of Finance and Revenue of the District of Columbia by the owner or user, for the issuance of a certificate as required by this subchapter, fees to be fixed from time to time by the Mayor of the District of Columbia for the annual inspection of each steam boiler or unfired pressure vessel, commensurate with the cost of inspection, with power to fix higher fees for the issuance of a certificate where the inspection in connection therewith is made on a Sunday or legal holiday. When an inspection report is filed by an insurance company with the said Boiler Inspector showing that a boiler or unfired pressure vessel has been inspected and found to be in a safe and insurable condition as provided in § 2-107 , the owner or user of such insured and inspected boiler or unfired vessels shall be exempt from the payment of all fees with the exception that there shall be paid to the Director of the Department of Finance and Revenue of the District of Columbia a fee of $1 by the owner or user prior to the issuance of a certificate of inspection. No such certificate shall be valid after the boiler or unfired pressure vessel shall cease to be insured by an insurance company authorized as provided in § 2-107 .