A fire starts.

Smoke rises.

Firefighters arrive.

And one of the first things they need is a reliable source of water.

Hidden beneath streets and connected across entire cities is a massive engineering system designed for one purpose:

Delivering thousands of gallons of water exactly when it is needed.

Fire hydrants may look like simple metal posts on sidewalks.

But they are the visible part of an enormous network of pipes, pumps, valves, reservoirs, and pressure systems working together to protect communities.

We examine how fire hydrants connect to underground water mains and how engineers design networks capable of supplying enough water pressure and flow for firefighting operations.

But delivering water to a fire is not as simple as opening a valve.

Engineers must calculate pipe sizes, ...