A bstract Aim This present longitudinal, quantitative, and analytical pilot study evaluated the impact of daily indirectly supervised toothbrushing on water consumption. Materials and methods The study was carried out in a social center that provided care to children aged 5–14 years in Campinas in the state of São Paulo. Calibrated hydrometers were installed on taps used by the children, and the daily volume of water used was measured for 25 school days (T0). An educational program was then implemented (T1), where supervised toothbrushing was explained, encouraged, and put into action. The next phase (T2) incorporated a recreational approach to the rational use of water, and the consumption was measured for another 25 school days. After six months (T3) without further educational interventions by the researchers, water consumption was measured for the same period of 25 school days. The data were analyzed based on the mixed models methodology for measures repeated over time. Results The water consumption did not change significantly ( p > 0.05) between the different phases of the study (T0 = 0.43 ± 0.19, T1 = 0.38 ± 0.17, T2 = 0.39 ± 0.15, T1 = 0.48 ± 0.21 dm 3 /day/child). Conclusion The introduction of toothbrushing into the routine of the children, in the context of recreational and sustainable health education, did not have a detrimental impact on water consumption. Clinical significance Among the many recommendations for the introduction and implementation of supervised toothbrushing programs in school environments, there is no mention of the measures taken during such procedures aimed at economizing water, the rational use of which should be a daily practice irrespective of the water conditions of the surrounding region. The findings of this study contribute to the enhancement of educational and pedagogical activities in schools. How to cite this article Flório FM, dos Santos Klee L, Brandão Ramos AP, et al. Use of Water by Schoolchildren: Impact of Indirectly Supervised Daily Toothbrushing—A Pilot Study. Int J Clin Pediatr Dent 2020;13(5):513–517.