Water by gravity
A Roman aqueduct brought water from distant hills to a city with no pumps at all. The water simply ran downhill the whole way, from spring to fountain.
The spring
It begins at a clean, steady spring high in the hills. Engineers walled it in and led the water into the channel.
A gentle slope
The covered stone channel drops very slightly and evenly, often less than a metre per kilometre. That keeps the water moving without wearing the channel away.
Arches across the valley
Where the ground dips, the channel cannot follow it down. Rows of arches on stone piers carry it across at the right height, the piers getting shorter as the line keeps falling.
The settling tank
Before the city, the water slows in a settling tank. Sand and grit sink to the floor and the cleaner water flows on.
Fountains and baths
A distribution tank splits the flow into lead pipes: public fountains first, then the great baths, then private houses that paid for a connection.