This article aims to show that in-depth ethnography of processes and acts of sociotechnical tinkering provide a useful starting point for understanding how water knowledge co-creation works. This is even more relevant in countries with a strong legacy of settler colonization and continued power asymmetries between holders of different water-related knowledges and ontologies. Analyzing infrastructural and sociotechnical forms of tinkering helps understand how various water assemblages interact with official norms, strategies and laws. Drawing on the study of this tinkering practice, this article looks at how the people of Touho, in New Caledonia, assemble different forms of knowledge to understand, access and drink water.