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Manual Tank Gauging

How does the release detection method work?

This method involves keeping the tank undisturbed for at least 36 hours each week, during which the tank's contents are measured, twice at the beginning and twice at the end of the test period. Manual tank gauging can be used as the sole method of release detection for the life of the tank only for tanks up to 1,000 gallons. Tanks between 1,001 and 2,000 gallons that meet diameters identified in the Table of Test Standards for Manual Tank Gauging below can use this method only in combination with tank tightness testing. This combined method, however, can be used only during the first 10 years following tank installation.

The features of manual tank gauging are:

What are the regulatory requirements?

Will it work at your site?

Manual tank gauging is inexpensive and can be an effective release detection method when used as described above with tanks of the appropriate size.

Anything else you should consider?

You can perform manual tank gauging yourself. Correct gauging, recording, and interpretation are the most important factors for successful tank gauging. The accuracy of tank gauging can be greatly increased by spreading product-finding paste on the gauge stick before taking measurements.

Will you be in compliance?

Manual tank gauging can only be used for smaller tanks. Tanks 1,000 gallons or less can use this method alone, but tanks from 1,001-2,000 gallons can only use manual tank gauging when it is combined with tank tightness testing. Manual tank gauging cannot be used for tanks over 2,000 gallons. When performed according to recommended practices, manual tank gauging meets the federal release detection requirements for USTs with a capacity of 1,000 gallons or less for the life of the tank.

USTs installed or replaced after [180 days after effective date] may no longer use manual tank gauging as the primary method of release detection. USTs must be secondarily contained and use interstitial monitoring.

More Information On Manual Tank Gauging

EPA's booklet, Manual Tank Gauging: For Small Underground Storage Tanks, explains how to do manual tank gauging with simple step-by-step directions. The booklet also includes standard forms used to record inventory data.

Table of Test Standards for Manual Tank Gauging

Tank Size Minimum
Duration of Test
Weekly Standard
(1 test)
Monthly Standard
(4 test average)
up to 550 gallons 36 hours 10 gallons 5 gallons
551-1,000 gallons (when
tank diameter is 64")
44 hours 9 gallons 4 gallons
551-1,000 gallons (when
tank diameter is 48")
58 hours 12 gallons 6 gallons
551-1,000 gallons
(also requires periodic
tank tightness testing)
36 hours 13 gallons 7 gallons
1,001-2,000 gallons
(also requires periodic
tank tightness testing)
36 hours 26 gallons 13 gallons

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