The Millennium Development Goals helped rally the world around the challenge of providing access to improved water supply and sanitation (WSS). By 2015 hundreds of millions of people had gained access to improved water sources and better sanitation. Despite this, with hundreds of millions more still lacking access, much remains to be done. Sustainable Development Goal 6 (SDG 6) significantly raises the level of ambition for the water sector, calling for universal access to safe water and sanitation while addressing issues of water quality and scarcity to balance the needs of households, agriculture, industry, energy, and the environment over the next 15 years. A substantial increase in sector financing will be necessary to achieve SDG 6. Recent estimates by the World Bank’s Water and Sanitation Program (WSP) indicate that the present value of the additional investment in WSS alone needed through 2030 will exceed US$1.7 trillion (Hutton & Varughese 2016). Existing funding falls far short of this amount; countries may have to increase their investment in the water and sanitation sectors by up to four times in order to meet the SDGs.