B-1.1, r. 3 - Safety Code

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144. Every day the owner uses the equipment, the owner must
(1)  gauge all underground tanks and read all dispenser meters; and
(2)  reconcile receipt and withdrawal records for each underground tank with the daily gauge readings taken pursuant to subparagraph 1.
If, however, the owner of high-risk petroleum equipment does not use the equipment for more than one week, the owner must gauge the equipment once a week during the period the equipment is not used.
O.C. 221-2007, s. 1.