From the aquifer, that is, from underground. The water is extracted through 433 active wells by the water supply system. From the wells, the water is drawn from a depth of between 60 and 120 metres and transferred to the stations, where it is filtered and purified to make it fit for drinking using extremely advanced technological systems. From the stations, it is distributed to the public via the 2,228 km of piping of the Milan water supply system. There are 29 active pumping stations distributed across the entire municipal area.