The main milestones of the Agua Santa nitrate office that turned it into the most emblematic one in the province of Tarapacá and all of Chile during the expansion of nitrate mining, which concludes with the First World War, are analyzed. It is suggested that its success was due to factors that turned Agua Santa into a pivotal space. The historical relevance that Agua Santa reached during the 'Chilean period' is explained, becoming, on one hand, a model of what nitrate technology was, and, on the other hand, building an urban space in the Atacama Desert. The 'Peruvian period' of Agua Santa is analyzed in more detail since it is less known and because it is key to understanding its success after the Pacific War.