Well into the 21st century, safe and affordable drinking water remains an unmet human need. Globally, at least 1.8 billion people are potentially exposed to microbial contamination in their drinking water on a regular basis (Onda, LoBuglio, and Bartram 2012). These people are found disproportionately in low-income households located in developing countries; nearly half of all people without access to an improved water source live in Sub-Saharan Africa, while one fifth live in Southern Asia (WHO/UNICEF 2015). Attempts at increasing access to safe water include a wide range of scales, from urban piped water networks providing services to millions of people, to Household Water Treatment and safe storage Systems (HWTS) which allow individuals to provide safe drinking water to their family. Encouraging uptake across a population and ensuring consistent and correct usage are vital for the creation of improved health outcomes from HWTS interventions. For urban water utilities and community systems, assessing and addressing health risks, planning successful upgrades and forecasting revenue streams requires an understanding of how people access, collect and store water, as well as their willingness to pay (WTP) for water services. In the cases of both HWTS interventions and piped water systems, addressing this public health issue requires an understanding of the perspectives, preferences, access points and financial means of end-users, especially those at the lowest income levels and in the most inaccessible locales.This dissertation has focused on two different case studies: one in rural Tanzania and the other in urban India. In both locations our teams collected observations regarding preferences and current practices of water access and usage. We measured WTP across a variety of potential options for drinking water treatment and access in both locations. In the city of Hubli-Dharwad, India, I evaluated a pilot project, measuring stated WTP for both end-users experiencing continuous water service (CWS) and those experiencing intermittent water service (IWS). In four rural villages of Tanzania we asked local residents to evaluate six HWTS, and then collected information on user preferences and WTP. For both locations I analyzed our observations with current policy debates in mind, and gave recommendations for both future research as well as the local management of domestic water systems. These two very different locations have little in common except for a need to improve access to safe drinking water; my research provides vital information on how to create interventions that people want and need. The results from Tanzania are relevant for other countries in Sub-Saharan Africa, as well as other developing regions with limited access to improved water sources and high rates of turbidity. The results from Hubli-Dharwad are relevant to other urban areas in South Asia, and IWS piped water networks in other developing regions as well.The knowledge generated in both locations also contributes to the literature on user preferences and WTP for water services. For the HWTS literature, my research addresses questions about why some HWTS interventions may have failed to scale up to a larger population or to sustain usage among participating households over time; namely that taste, smell, aesthetics, familiarity and ease of use are all vital components of an individual’s decision as whether or not they will treat their drinking water. For this reason, boiling deserves reconsideration as a potentially important option for future HWTS interventions. WTP for retail HWTS is non-zero for the majority of households even in a highly impoverished location such as rural Tanzania, but it is still far below retail prices. The user preferences and WTP analysis for in Hubli-Dharwad sheds light on what piped water services are valued by end-users, and gives some indications on whether and when they should be pursued, adding to the research literature concerning urban utility management and informal urban services. In particular, three key findings emerge from my work there. The first is that CWS may not always be the best upgrade option, and may not provide all of the benefits that it usually is assumed to provide, depending on the experiences, preferences and beliefs of the local end-users. Second, a subset of low-income households depends on free supplemental water sources and therefore service upgrade projects should not include their removal. And finally, water quality is important, but taste and smell can confound households’ perceptions of water quality, and therefore water aesthetics are a salient issue that may deserve greater attention in the future.