4.4.2 Frequency & Detection Rate
Inventory reconciliation must be performed at least monthly, and must be able to detect a leak rate of 0.5 percent of total throughput on a monthly basis for each tank. (For example, 0.5 percent is equal to 5 gallons out of every 1,000 gallons of throughput.)
Any loss greater than 0.5% must be considered a suspected release, and will require an investigation to determine the exact nature of and reason for the loss. (See Chapter 8 – Release Response & Reporting)
Inventory control must be performed using the same method each day and each month. Instructions for how to perform inventory control can be found at Inventory Control Record Templates.