Singapore is the third most densely populated country in the world, but also sixth in the world in per capita nominal GDP for a country, meaning that there are considerable resources available to solve challenges generated by such high population density. As an island nation, Singapore is greatly limited by both space (e.g., for living, waste disposal, water storage), and available in-country natural resources (e.g., freshwater, energy sources). Water security has long been a national priority for Singapore, as it has historically imported most of its freshwater from neighboring Malaysia. The two-country agreement ends in 2061, and by that time, Singapore plans to be fully self-sufficient in its freshwater needs. Singapore outlined its strategy to generate a portfolio of diversified water resources in its 1972 Water Master Plan. This plan’s approach to self-sufficiency in water supply was three-pronged: build more desalinization plants; collect more run-off during rain events; and greatly increase wastewater recycling. To address the latter approach, and to simultaneously help solve other intense problems it faced as a small island nation (pollution, solid waste disposal and energy), Singapore developed one of the most efficient and integrated wastewater systems in the world. A key facet in this system is the world’s largest wastewater energy recovery facility, which is located next to the largest water reclamation plant in the world (Tuas WRP). Together, the facilities efficiently collect, treat and discharge used water, enhance water sustainability by enabling large-scale water recycling, and reap the potential synergies of the water-energy-waste through sludge incineration. By locating facilities next to each other, huge efficiencies are generated, including reduced/eliminated transportation costs and greenhouse gas emissions. On the recycled water side, one of the more important technological advances Singapore has made is the development of the NEWater system. Through a four-step series of barriers and membranes, wastewater is made free of solids, microorganisms, nutrients, and contaminants, resulting in potable water supplies that can be delivered directly into the public water supply. After one decade, this technology generates 40% of the water needs of Singapore. Of course, another key wastewater policy is to decrease wastewater generation. In 1991, Singapore initiated a water conservation tax (graded on income), that was designed to provide an incentive to increase efficiency in water use by households and business, and also provide funds to support innovation in wastewater recycling technologies. This tax has been successful, and has been increased more recently to further fund technology advancement and incentivize conservation.