The political ecology of historical urban water systems can yield information on the long-term, social organization of resource infrastructure and its management. In this article, the water system of Piacenza, Italy, is examined through its history and the documents of the Congregazione sopra l'ornato, the committee in charge of water management in the city, under the Farnese dukes, from 1545 to 1736. The documents include letters from residents, responses and orders from the committee, tax documents and engineering reports. These records tell a story of a water system and its relationship to the city residents.