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Tank Tightness Testing with Inventory Control

When performed according to the manufacturer's specifications, periodic tank tightness testing combined with monthly inventory control can temporarily meet the federal release detection requirements for tanks (this method does not detect piping leaks). Inventory control alone does not meet the federal requirements for release detection for tanks.

Tightness testing (if conducted at least every 3 years) is also an option for underground piping.

Tank Tightness Testing

How does tank tightness testing work?

Tightness tests include a wide variety of methods. Other terms used for these methods include precision, volumetric, and nonvolumetric testing.

The features of tank tightness testing are:

What are the regulatory requirements for tank tightness testing?

Anything else about tank tightness testing that you should consider?

Inventory Control

How does inventory control work?

Inventory control requires daily measurements of tank contents and mathematical calculations that let you compare your stick inventory (what you've measured) to your book inventory (what your recordkeeping indicates you should have. If the difference between your stick and book inventory is too large, your tank may be leaking.

EPA's booklet, Doing Inventory Control Right, explains how to do inventory control with simple step-by-step directions. The booklet also includes standard forms used to record inventory data.

The features of inventory control are:

What are the regulatory requirements for inventory control?

Anything else about inventory control that you should consider?

Time restrictions on the use of this combined method...

USTs installed on or before [180 days after effective date] may use this method for 10 years after the date the tank was installed or upgraded with corrosion protection. Note that the end date is based on the compliance status of the tank only, not the entire UST system. As a result, some USTs may not be able to use this combined method for as long as 10 years. At the end of the valid period, you must use one of the monthly monitoring release detection choices described herein.

USTs installed or replaced after [180 days after effective date] may no longer use inventory control combined with periodic tank tightness testing as the primary method of release detection. USTs must be secondarily contained and use interstitial monitoring.

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