Pursuant to the District of Columbia Underground Storage Tank Regulations, Title 20 DC Municipal Regulations (DCMR) §§ 6208, 6209 and 6210, the Toxic Substances Division, Underground Storage Tank (UST) Branch has established numerical standards for soil, surface water, and ground water quality. All soil and water samples must be analyzed by an EPA-approved method, as directed by the LUST Case Manager of the District Department of the Environment. The Tier 1 Risk Based Screening Levels for Soil and Groundwater are listed in the document titled: Tier 1 RBSLs for Soil and Groundwater (see below).
Soil Quality Standards: These standards shall be used as a guideline for completing the Comprehensive Site Assessment. Note that Tier 0 Screening levels listed in 20 DCMR 6208 are updated as Tier 0 Screening Levels for Soil (see below).
Surface Water Quality Standards:
The standards for surface water quality are the District of Columbia Water Quality Standards (21 DCMR Chapter 11, published at 41 DC Register 1075, March 4, 1994).
Ground Water Quality Standards:
The standards for ground water quality for specific inorganic and organic compounds are the District of Columbia Water Quality Standards for Ground Water (21 DCMR Chapter 11, published at 40 D.C. Register 4203, July 2, 1993). The maximum contaminant levels (MCLs) for the most common compounds of interest at LUST investigations:- Benzene: 5 ppb; Toluene: 1,000 ppb; Ethylbenzene: 700 ppb; and Total Xylenes: 10,000 ppb.