The invention relates to a method for operating tank farm systems, which are interconnected with pipes in a fixed manner and which have pipe systems for liquids, particularly for use in systems which are subject to high microbiological quality requirements and which are used for processing and transferring products in the foodstuffs and beverage industry, pharmaceutical industry, and biotech industry. The invention provides that the supply and discharge of liquids into and out of the respective tank ensues from underneath, and that the liquids that are being supplied or discharged flow through a space which is directly connected to the respective tank contents and which is situated underneath the respective tank in a switchable manner, and in a manner that ensures mixing, from the pipes of the pipe system that lead to this space.