A firm providing essential services to the public, such as water, electricity and postal services, usually involving elements of natural monopoly. Food is essential, but because it is provided in a competitive market, food supply is not usually regarded as a public utility. Because public utilities have some monopoly power, they are typically subject to some regulation by government, such as price controls and perhaps an obligation to provide their services to everybody, even to those who cannot afford to pay a market price (the universal service obligation). Public utilities are often owned by the state, although this has become less common as a result of privatization.