A public utility is an entity that provides the general public with essential goods and services such as electricity, natural gas, energy, water, sewer, heat, telecommunications (telephone, fiber optic or broadband internet), railroad, and rail transit.

Public utilities (goods and services) are often provided by a public utility corporation that is essentially given a monopoly over the provision of the good or service in a certain geographic area—and exemption from antitrust and unfair competition laws—in exchange for certain governmental restrictions and regulations. Public utility companies are often regulated by a governmental Public Utility Commission (PUC).

The laws and rules that govern public utilities are usually located in state or federal statutes—depending on whether the utility is regulated by the state or federal government. For example, many states have a public utilities code—sometimes called a public utility regulatory act—or provide for public utility corporations and their regulation in the state administrative code. The Federal Energy Regulatory Commission (FERC) is one example of a PUC at the federal level.

In Alabama, public utilities such as electricity, natural gas, water, and telecommunications are regulated primarily by the Alabama Public Service Commission (PSC). The PSC is responsible for ensuring that these essential services are provided to the public in a fair, efficient, and reliable manner. The commission sets rates, handles service complaints, and oversees the operations of public utilities to ensure compliance with state regulations. Utilities are often granted a monopoly in a specific geographic area, but in return, they are subject to regulatory oversight which includes rate approval and service quality standards. While the Alabama PSC regulates most of the state-level utility services, federal-level regulation is handled by agencies such as the Federal Energy Regulatory Commission (FERC), which oversees interstate electricity sales, wholesale electric rates, hydroelectric licensing, natural gas pricing, and oil pipeline rates. The interplay between state and federal regulation depends on the scope and reach of the utility service in question.