Near the second "butto" there is a cistern for the collection of rain water, later cut into for the staircase of the wine cellar.

This large reservoir dates to Etruscan times, as indicated by the waterproofing plaster still visible on the inner wall built with well-ground terracotta fragments mixed with lime, according to a tech-nique called "cocciopesto".

Water was collected from the roofs and was carried through terra cotta tubes [like those exhibited at the bottom of the cistern] to the reservoir after passing through a layer of filtering material.