The water supply and sanitation sector remains heavily subsidized around the world. Yet, the accounting of water supply and sanitation subsidies globally has proved challenging due to utility-level data limitations and their often implicit nature. This paper develops a methodology to estimate water supply and sanitation subsidies that is adaptable to data scarce environments, while accounting for differences among service providers such as population served (to account for economies of scale), coverage of water and sanitation services individually, and their level of operational efficiency in terms of water losses and staffing.