In ten videotaped socio-scientific debates related to water,students from Mexico, the USA and France tend to focus on afew alternative positions. On the basis of Grize’s definition ofschematization, we followed their reasoning by studying howthey cast light on specific aspects of the discursive object“water”. Through textometrical analysis of debate transcripts,we specified 6 characteristics of “water” that are more or lessemphasized depending on the prevailing nationalargumentative scenario.