Recent research suggests that establishing water clubs in care homes can counteract the dangers of dehydration and enhance residents' health and well-being. This study provided an experimental test of this idea, and also explored the possibility that it is the social interaction that clubs provide which delivers health-related benefits. Consistent with this hypothesis, the study found no evidence that, on its own, increased focus on water consumption enhanced residents' health or well-being. However, residents who took part in water clubs showed improved levels of perceived social support, and those who participated in water and control clubs showed beneficial outcomes in terms of the number of General Practitioner calls they required. Consistent with a social identity approach to health and well-being, a mediation analysis also indicated that clubs achieve these positive outcomes by providing social support that helps to build a shared sense of social identity among residents.