To detect defects in the metal structures of vertical steel tanks, in addition to visual inspection, ultrasonic methods are most often used for diagnosis: thickness gauging and flaw detection of metal, flaw detection of welds. The current level of technology makes it possible to mechanize and/or automate the use of these methods, including registration of identified defects in connection with the inspected product. However, these methods have a number of disadvantages that complicate their use. For example, for mechanized scanning conditions, reliable methods for detecting transverse cracks in the presence of reinforcement rollers have not yet been developed. Also, ultrasonic testing reveals, much worse than plane defects, fistulas of corrosion origin, including through ones, which can lead to local leaks of the product onto the outer surface of the tank wall. Meanwhile, defects of these types are the most dangerous among those that arise during longterm operation of tanks. Their identification during diagnosis is necessary. In addition, the accuracy of estimating the size of other types of defects with mechanized and/or automated ultrasonic testing is usually lower than with classical manual testing. Based on an analysis of literature data and our own theoretical studies, recommendations have been proposed, the implementation of which makes it possible to increase the detectability of transverse cracks in welds while maintaining a sufficiently high detectability of planar defects oriented along the axis of the welds both in linear sections and in the cross zones of butt welds. It is indicated that in order to provide better conditions for identifying vertical fistulas, it is advisable to adjust the parameters of ultrasonic testing for vertical drillings. At the same time, it is possible to simplify the requirements for the positioning accuracy of transducers during mechanized scanning.