A public utility (usually just utility) is an organization that maintains the infrastructure for a public service (often also providing a service using that infrastructure). Public utilities are subject to forms of public control and regulation ranging from local community-based groups to statewide government monopolies.
The term utilities can also refer to the set of services provided by these organizations consumed by the public: electricity, natural gas, water, and sewage. Broadband internet services (both fixed-line and mobile) are increasingly being included within the definition.
In the United States, public utilities are often natural monopolies because the infrastructure required to produce and deliver a product such as electricity or water is very expensive to build and maintain. As a result, they are often government monopolies, or if privately owned, the sectors are specially regulated by a public utilities commission. The first public utility in the United States was a grist mill on Mother Brook in Dedham, Massachusetts.