This study examines how the development of water supply management happens over time in distinct types of informal areas in Mumbai and Nairobi. The financial differences and political barriers in both cities, together with the vast diversity factors, development patterns, and challenges of each study area show that reconsidering different approaches is significant in developing more inclusive paradigms in water provision in informal areas. Relevant to these concerns, this study aims to clarify water practices and explore inclusive ways of developing water supply management through the analyses of water provision modes and network systems in each study area. A series of field studies on the type of water sources and facilities, parties involved in water practices, and characteristics of water development was performed in six case studies (i.e., three in Mumbai and three in Nairobi) from 2014 to 2019. The main findings of this study show that an unconventional informal tenure system constrains the settlement typology and development of the physical access of service facilities in study areas. Moreover, the different measures taken by Mumbai and Nairobi in providing water supply to informal areas result in an unequal path for water development and various vulnerability levels. Therefore, we argue that the mixtures of policy- and practice-rooted practices ensure a more inclusive water development because they would lead to the sociotechnical arrangements of the technical system and institutional arrangements that better fit the local conditions characterized by different spatial structures and social variables.