OBJECTIVES: Despite a Commission of Inquiry into water fluoridation recommending the fluoridation of public water supplies to the optimal fluoride concentration of 0.7 ppm, as well as regulations for the introduction of water fluoridation which compel water providers to fluoridate public water supplies, no artificially fluoridated water scheme exists in South Africa. In view of concerns expressed by South African local authorities about cost and reports urging further investigation into the effectiveness of water fluoridation, the aim of this study was to determine whether water fluoridation is still a viable option to reduce dental caries in South Africa. METHODS: A model based on a cost evaluation of 44 communities in Florida, United States, and applied to South Africa was used as the basis for this study. Twenty-three input variables were used to create a computerized model which was populated with 2006 and 2011 data. Per capita cost, cost-effectiveness ratio and cost-benefit ratio were calculated as economic outputs to facilitate decision making for projected caries reductions of 15%, 30% and 50%. RESULTS: The average per capita cost of water fluoridation for all category water providers combined is US$0.28 in 2006 and US$0.35 in 2011, an increase of 23.2% over this period. The average costeffectiveness for all water providers combined varies from US$3.32 for a 50% to US$11.08 for a 15% caries reduction. Despite higher cost-effective values for some cities and towns, the cost per person per year to save one Decayed, Missing or Filled Tooth (DMFT) at a projected caries reduction of at least 15% as a result of the introduction of water fluoridation, is at least 48.4% less than the cost of a two surface restoration. The average cost-benefit for all water providers combined varies from 0.1 at a 50% to 0.34 at a 15% caries reduction. For both cost-effectiveness and cost-benefit ratio better results are achieved when the projected caries reduction increases. CONCLUSIONS: The results of this study show that water fluoridation is still a viable option to prevent dental caries in communities in South Africa along with the reduction in the prevalence of dental caries and increases in economically driven variables.