The EPA/DEC have guidelines for this SPCC – Spill Containment Counter Measure requirement. Based on the SPCC requirement, you must ensure your containment area has enough capacity to contain at least 10% of the total volume of the primary containers, or 100% of the volume of the largest container, whichever is greater. We have a spreadsheet that provides a rough estimate of the height and size containment berm you will need. Please consult with your licensed engineer/P.E. for certification and full requirements.