Which component of a UST system is primarily responsible for storing the liquids?

The component primarily responsible for storing liquids in a UST (Underground Storage Tank) system is the tank itself. The tank is designed to hold various types of liquids, such as fuel, for extended periods. It is built to withstand environmental stresses and is constructed from materials that can safely contain the liquid without leakage or degradation over time.

Monitoring systems, piping, and containment play crucial roles within the UST system, but their functions are not centered around storage. Monitoring systems are used to track the status and conditions of the tank, including levels and potential leaks. Piping transports the liquids to and from the tank, facilitating access and distribution. Containment structures protect the environment by preventing spills and leaks from affecting the surrounding area but do not store the liquids themselves. Thus, the tank is the key component that holds the liquids in a UST system.