Abstract: Climate change is having increasing impacts on water, sanitation, and hygiene (WASH) worldwide, rendering health-friendly behaviours less achievable in low-resource settings, disrupting WASH service provision, and reversing global progress on improving WASH infrastructure and controlling waterborne diseases. Much of these impacts are mediated through climate-driven changes in rainfall, which lead to both intensified and lengthier droughts, alongside heavier bouts of rain, and more frequent storms and extreme weather events. The impacts of both extreme and minimal rainfall on water quality and access and on sanitation and hygiene maintenance are myriad and have gained increased attention owing to a growing body of literature presenting important social, health, and environmental consequences. In recent years, a rising number of actors have pointed to the need for climate adaptation to be mainstreamed into the WASH sector, to ensure that WASH services, technologies, practices, and infrastructures are maximally resilient to the impending impacts of climate-driven rainfall changes. In the Lake Victoria Basin (LVB), which encompasses parts of Kenya, Uganda, Tanzania, Rwanda, and Burundi, both WASH and, more recently, climate change have been placed relatively high on the agenda of development bodies. A history of WASH progress in this region has notably reduced waterborne disease incidence, but ongoing threats still produce significant morbidity and mortality burdens. Meanwhile, the region is highly vulnerable to climate change due to a combination of geographic, hydrological, and socioeconomic factors. Not surprisingly, East African governments have had to devote increased attention to climate adaptation goal-setting, as the impacts of climate change on the region become more pressing and the United Nations Framework Convention on Climate Change pushes for regular submission of National Adaptation Plans and National Adaptation Programmes of Action. Given the importance of both climate adaptation and WASH in the LVB context, and the growing impetus for climate-WASH integration, this study sought to assess the progress thus far achieved in integrating WASH and climate adaptation agendas in the LVB, and outstanding barriers to progress. A secondary objective was to better understand how lakeside communities are adapting their own WASH behaviours and practices in response to the new threats posed by climate change-driven changes in rainfall, so that any positive adaptations could be documented, and associated innovations later tapped in regional climate adaptation planning efforts. Through a collaboration with a community-based organization in Western Kenya named Kar Geno- Center for Hope, a quantitative WASH practice survey was conducted, followed by 17 qualitative interviews and 17 focus groups with community members residing in the lakeside village of Mabinju, located in Siaya County. Collaborations were additionally forged with a network of organizations working on WASH and/or climate adaptation in the wider LVB region, from which knowledgeable stakeholders were interviewed. Interviews and focus groups, which were conducted in Luo but translated into English, were recorded and transcribed, and a qualitative thematic content analysis was conducted on all transcripts. This involved inductive coding using Dedoose qualitative data analysis software and a grounded theory analysis framework. The results of the study affirmed the cross-cutting impacts that climate change is having on WASH in the region, at both community and governance levels, and illuminated how it has interacted with other environmental threats to accelerate longstanding trends of environmental degradation and socioeconomic vulnerability. The responses of community members in Mabinju to these impacts were found to be wide in scope, and included both positive and maladaptive behaviour changes. On an institutional level, sectoral siloes and a lack of interdisciplinary collaboration, among other factors related to funding and international priorities, were found to restrain full climate-WASH integration in the region, despite evidence of early progress. Attention paid to sanitation was also found to be notably lacking, paralleling a global trend of disproportionate focus on water within the broader climate adaptation agenda. These findings hold implications for regional climate adaptation planning efforts, and offer global lessons on how governance structures can be made more conducive to climate-WASH integration and on how community knowledge, insights, and innovation potential can be better tapped in the development of novel climate resiliency promoting measures in the WASH sector.