This paper outlines the major challenges related to financing the gap in global water infrastructure, including those systems that provide urban and rural water supply, and sanitation and irrigation services. The paper synthesizes the extensive body of literature on this subject, providing some examples of historical trends and proposing a reform agenda to assist countries in weathering the current financial climate. Section 1 introduces the linkages between water infrastructure and growing global challenges, including food and energy security as well as climate change. Section 2 describes investment needs in the sector and details various traditional funding sources. Section 3 proposes a 5 step reform cycle for making better use of limited funding in the sector. Tools for making these improvements are outlined in Section 4. The paper concludes with Section 5, a summary of the challenges and recommendations for the way forward.