Only some of the water flowing in an aqueduct reached the town. On average, about thirty per cent was diverted along the way to supply villas or irrigate farmland. The rest entered the walls of a city, often more than 24 hours after leaving its source. As was common throughout the empire, the Los Milagros aqueduct ended in a castellum divisorium. Although castellum is a military term meaning a defense post on a wall, this particular castellum was just a large tank.