ABSTRACT The aim of this study was to analyze the costs of fluoridation in water supply systems of different population sizes. A case study was carried out comprising cities in the state of Espírito Santo, Brazil. The costs of initial installation, the chemical product, the operation of the system, and the control of fluoride levels between the years 2012 and 2017 were considered. The annual per capita cost of the treatment was calculated to estimate the fluoridation weight concerning the total expenses. The fluoridation annual per capita cost ranged from R$ 20.14 (US$ 7.23) in towns with less than two thousand inhabitants to R$ 0.39 (US$ 0.14) in cities with a population of approximately 520 thousand inhabitants. In systems that supply up to 30 thousand inhabitants, the running cost was responsible for most of the expenses, ranging from 98.2 to 84%. For cities with 520 thousand inhabitants, the costs with the chemical product corresponded to 74.7% of the expenses. Compared with the total treatment cost, the water fluoridation cost ranged from 0.2 to 0.6% for population sizes of 30 thousand inhabitants or more and varied from 1.3 to 7.3% for towns with less than 10 thousand inhabitants. Considering that the decision-making process is complex in the field of public policies, and decision-makers suffer multiple influences as for different policy alternatives, knowing the implications of population size for costs is essential for informed decision-making.
A multi-criteria decision making approach to balance water supply-demand strategies in water supply systems