Dug into the living rock, it was originally around 40 km long, bringing water directly from Monte Lauro. In later times it was shortened to a length of 29 km, drawing water from the sources of the Calcinara river, near Pantalica down to the higher parts of the city, near Neapolis. It carried around 500 litres per second. The work is considered a masterpiece of hydraulic engineering and conformed to the instructions later given by Vitruvius for the optimal slope. It is noted by him that this aqueduct, compared to other Greek aqueducts, had a great level of precision and was constructed with finesse.