The emergence of COVID-19 has created many unanticipated changes globally, particularly in terms of the availability and use of water resources. This study aims to estimate the potential increase in global domestic water use, exclusively due to the handwashing requirement for COVID-19. To assess the potential increase in domestic water use, this study analyzed population and water use data of 175 countries. Based on WHO guidelines, the additional water required for handwashing per person per day was estimated to be 0.018 m3 and was integrated with water use and population data for the analysis. These findings reveal that if everyone washes their hands six times a day solely to prevent the spread of coronavirus, global domestic water use and total water use would increase by about 11.96% and 1.25%, respectively. Africa (23.88%), Asia (15.05%), Latin America, and the Caribbean (7.18%) are anticipated to have the most significant increases in domestic water use due to the increased handwashing. This is a concerning phenomenon because these nations are already experiencing water shortages, even before the pandemic. These results may aid these countries in achieving Sustainable Development Goal 6, by guiding stakeholders and decision-makers to take action to address the water resource management challenges posed by the unexpected rise in water use caused by events such as COVID-19.