The way I understand it in my country is this:

There is only one public water system, every house connects to it. The state tasks specific companies with its maintenance (these are often not utility providers themselves, just construction/maintenance companies).

Consumers attached to that system have a metered connection, but water just flows as long as there's enough overall. Your utilities company doesn't have to move any physical water at all. They just have to eventually "settle" the amount of water that they sold to their customers. They do so by buying and then forwarding options contracts. The electricity and gas companies are the same. They compete on

- trading (who knows best when to buy how much?) and

- consumer-facing marketing

This is how a lot of the modern economy works. Through the power of abstraction, you can run an online store without producing or shipping any items yourself and a delivery restaurant without cooking any meals.