Mississippi Administrative Code
Title 11 - Mississippi Department of Environmental Quality
Part 5 - Underground Storage Tank Regulations
Chapter 2 - Mississippi Commission on Environmental Quality Underground Storage Tanks Regulations Technical Standards and Corrective Action Requirements for Owners and Operators of Underground Storage Tanks (UST) (Adopted March 22, 1989; Amended August 25, 2011, Last Amended August 23, 2018)
Appendix 11-5-2-280.4 - GUIDELINES FOR THE PERMANENT CLOSURE OF PETROLEUM UNDERGROUND STORAGE TANK SYSTEMS
Section 11-5-2-280.4-3 - SAMPLING PROCEDURES
Section 11-5-2-280.4-3-3.2 - Soil Versus Groundwater Samples

Soil samples must be collected whenever evidence of soil contamination exists. However, if water is encountered, pump it out in accordance with all regulatory requirements and determine if the water in the tank excavation or borehole returns within 24 hours. If the water returns, assume that the water is true groundwater. If groundwater is present, water sample(s) must be collected. If groundwater is sampled, no soil sampling is required unless soil contamination is evident. If soil contamination is evident at either the tank excavation or the piping trench/dispenser island, soil samples must be collected in accordance with Sections 5-7 of this document in addition to any water samples.