D.C. Mun. Regs. tit. 20, r. 20-6013
An owner or operator of an UST system installed on or before February 8, 2007 may apply to the Department for approval of another method of release detection by submitting a written request describing the method to the Department in accordance with § 5500.5.
For UST systems installed on or before February 8, 2007, the Department may approve an application for the use of another method of release detection only if the owner or operator demonstrates that the method is capable of detecting a release as effectively as any of the methods allowed in §§ 6007 through 6012 and meets the requirements of this section.
The alternative release detection method, or combination of methods, shall be capable of detecting either of the following:
The alternative release detection method shall detect a leak rate or quantity in § 6013.3 with a probability of detection of at least ninety-five percent (95%) and a probability of false alarm no more than five percent (5%).
In comparing methods, the Department shall consider the size of release that the method can detect and the frequency and reliability with which it can be detected.
If an alternative method is approved, the owner or operator shall comply with any conditions imposed by the Department on its use.
For any tanks installed or replaced after February 8, 2007, alternatives to interstitial monitoring shall not be approved or used.
D.C. Mun. Regs. tit. 20, r. 20-6013