The Museo dell'Acqua, which opened in 2001 and belongs to the Water System of the Casentino Ecomuseum, is housed in the building of the "La Nussa" hydro-electric power station. The still functioning power station was built in the early 20th century on the site occupied, since the 18th century, by a mill. Destroyed by the Germans, it was rebuilt in 1946. The Museum is the point of departure for a thematic itinerary on water in the Casentino territory. Its purpose is to illustrate the various ways of using water, from fundamental alimentary resource to decisive element for the production of energy, indispensable to drive the machines of mills, fullers and ironworks.

The first section of the Museum is dedicated to the "waters of the valley", that is to the hydraulic network created around the River Arno and its tributaries. The second section describes the bridges that connect the various towns that have risen along the course of the Arno, and the structures of the river ports, such as those of Badia di Pratovecchio and Ponte a Poppi. The following sections explain the importance of water for the manufacturing and industrial activities of the Casentino valley; in particular, the "artificial machines" section illustrates the uses of water as motive power, and the various machines used in hydraulic mills. Finally, there is a section dedicated to the therapeutic aspect of water and the various springs with particular curative properties, such as the sulphuric-chalybeate waters of Chitignano or those of the ancient Cetica Baths.

The Museum also houses a laboratory where experiments can be conducted on the physical-chemical properties of water and on hydrodynamic principles. In particular, two sections are dedicated to education: the one entitled "Trickling Water: little experiments for great principles", makes it possible to illustrate, with simple instruments, the principles of capillarity, of communicating vessels, of the reaction turbine; the other one entitled "Wise Drops", presents a fascinating exhibition with the answers to curiosities about water that "rains from the roof".