Data for generating Fig C in S1 Text.

Billions of people globally are at risk for severe water scarcity periodically throughout the year. Moreover, intensifying climate change and increasingly unpredictable weather patterns will increase the severity and scope of those affected by household water insecurity, with negative consequences on household health and wellbeing. Faced with water insecurity, households shift to alternative water sources, which may be more expensive or of lower quality and contribute to both financial and health burdens. The extent to which household water insecurity varies throughout the year, however, remains understudied. Using a panel dataset of 2014 households across 40 villages in Matlab, Bangladesh, we test for seasonal variation in household water insecurity and its determinants using a modified HWISE scale. We find that while water insecurity in Matlab was low both pre- and post-monsoon, household water experiences vary throughout the year. Households report significantly lower water insecurity post-monsoon, compared to pre-monsoon, suggesting an annual measure of household water insecurity is insufficient to fully characterize intra-annual household water experiences. Comparing determinants of household water insecurity, we find that geography, household water use behaviors, and household characteristics are significantly related to experiences of household water insecurity but vary in their extent depending on the season. Our results demonstrate that physical location, seasonality, water quality, and household-level factors contribute to the dynamic nature of intra-annual household water insecurity. Knowing when and to what extent such determinants influence household water experiences throughout the year is essential for guiding and adapting engineering and policy design to reduce the costs and consequences of household water insecurity.