API inspection codes in general have a strange love—hate relationship with hydrotesting. Storage tanks are no exception — on one hand API 653 explains how and when it should be done, but this is followed up by a long list of valid scenarios for exemption. Unlike pressure equipment items, the underlying message is that (excluding new or fully reconstructed tanks) a hydrotest on a storage tank is something that you choose to do, rather then being forced to do so by API 653.