Abstract Oral health parameters were compared for 6–8 and 10–11‐year‐old children living in neighbouring N. S. W. towns, where the community water supplies consisted of artesian and river water respectively. The demographic characteristics, living pattern and dietary carbohydrate challenge were similar in the two areas and effective oral hygiene practices were uniformly lacking. Children in the artesian water area had 40% lower caries prevalence (DIMFT), 50% less severe carious lesions (SR)...