ATCP 93.515(2)(b)3.a.a. The inputs shall be reconciled with delivery receipts by measurement of the tank inventory volume before and after delivery.

ATCP 93.515(2)(b)3.b.b. Where tanks are interconnected by a manifold, reconciliation may address all of the interconnected tanks as a group rather than as individual tanks.

ATCP 93.515(2)(b)4.4. The measurement of any water level in the bottom of the tank shall be electronically or manually gauged to the nearest one-eighth of an inch at least once a month and recorded.

ATCP 93.515(2)(c)(c) Product losses. Tank systems that exceed the losses allowed under par. (b) for 2 consecutive months shall follow the requirements in ss. ATCP 93.575 to 93.585 for assessing and responding to a release.

ATCP 93.515(2)(d)(d) Precision tightness test. A precision tightness test shall be performed in accordance with sub. (4) within 10 business days of notification from the authorized agent or the department for any of the following reasons:

ATCP 93.515(2)(d)1.1. Failure to provide monthly inventory control data for the past 12 months.

ATCP 93.515(2)(d)2.2. Incomplete or inconsistent data entry reflected during any 2 months of data entry out of the most recent 3 months of inventory control record keeping.

ATCP 93.515(3)(a)1.1. Manual tank gauging may be used as the sole method of leak detection for tanks that have a capacity of 1,000 gallons or less for the life of the tank.

ATCP 93.515(3)(a)2.2. For tanks that have a capacity of more than 1,000 gallons to 2,000 gallons, manual tank gauging may be used if all of the following conditions are met:

ATCP 93.515(3)(a)2.a.a. The tank system has a precision tightness test performed in accordance with sub. (4) at least once every 5 years from the date of installation until the tank is ten years old.

ATCP 93.515(3)(a)2.c.c. The piping either receives an annual precision tightness test or has electronic line leak detection testing, and this tightness test or leak detection testing is performed in accordance with the capabilities specified in s. ATCP 93.130 (3) (b).

ATCP 93.515(3)(a)3.3. Tanks which have a capacity of more than 1,000 gallons to 2,000 gallons and which are more than 10 years old shall be provided with monthly monitoring in accordance with sub. (5), (6), or (7).

ATCP 93.515(3)(a)4.4. Tanks that have a capacity of more than 2,000 gallons may not use manual tank gauging as the method of required leak detection.

ATCP 93.515(3)(b)(b) Manual tank gauging procedures. Manual tank gauging shall meet all of the following requirements:

ATCP 93.515(3)(b)1.1. Liquid level measurements shall be taken with a gauge stick that is marked to measure the liquid to the nearest one-eighth of an inch over the full range of the tank’s height.

ATCP 93.515(3)(b)2.2. Tank liquid level measurements shall be taken at the beginning and ending of the test duration periods given in Table 93.515, during which no liquid may be added to or removed from the tank and shall be based on the average of 2 stick readings taken at both the beginning and ending of the period.

ATCP 93.515(3)(b)3.3. A leak is suspected and subject to the requirements of ss. ATCP 93.575 to 93.585 if the variation between beginning and ending measurements exceeds the weekly or monthly standards in Table 93.515.

1 Requires precision tightness testing every 5 years. This method is only allowed until the tank is 10 years old.

ATCP 93.515(4)(a)(a) Precision tightness testing shall be conducted in one of the following ways:

ATCP 93.515(4)(a)1.1. By a certified tank system tightness tester, using methods approved under s. ATCP 93.130 to perform precision tightness testing for tanks or piping.

ATCP 93.515 NoteNote: The approval criteria in s. ATCP 93.130 include capability of detecting a leak rate of 0.1 gallons per hour.

ATCP 93.515(4)(a)2.2. With permanently installed leak detection equipment as approved under s. ATCP 93.130 to perform precision tightness testing for tanks or piping.