D.C. Mun. Regs. tit. 20, r. 20-5606
In lieu of inspection by the Department, an owner or operator may request the Department to approve compliance inspections of UST system installations, upgrades, repairs, closures, release detection system(s), and manufacturer-required annual maintenance inspections performed by an independent third-party inspector who is a Department-certified UST System Technician.
If the Department approves use of an independent third-party inspector, the Department will accept the third-party inspector's report and findings if the report contains all the compliance inspection information required by the Department.
An independent third-party inspector may not certify an UST system if he or she has a financial interest in the UST system or the facility in which the UST is located.
D.C. Mun. Regs. tit. 20, r. 20-5606