There is widespread recognition that cities in the Global South need to transition toward sustainable water practices. This is particularly true of places experiencing growth and impacts from climate change concomitantly, as are Bangkok and Hanoi. We evaluate case studies in each of these two Southeast Asian cities to explore possible sustainable water management practices that their urban communities, and others experiencing similar issues, could adopt in the near term. Our analysis of these case studies supports four key conclusions: Simple expansion of rigid infrastructure does not necessarily meet local needs for water, communities can themselves provide insights and creative models, governments at any scale can be flexible and such flexibility can achieve appropriate solutions, and small-scale experimentation can and does work and can be successfully scaled up with government encouragement and support.