Water crises - defined as significant declines in water quality and quantity - top the global risks list compiled by the World Economic Forum (2015) that have the greatest potential impacts on society. Vegetation fires are amongst the most hydrologically significant landscape disturbances (Ebel & Mirus, 2014) and affect ~4% of the global vegetated land surface annually (Giglio, Randerson, & van der Werf, 2013). Fire‐prone or fire‐managed ecosystems (forests, grass‐, and peatlands) also provide ~60% of the water supply for the world's 100 largest cities (Martin, 2016). Accordingly, fire is increasingly acknowledged as a serious threat to water supply globally (Martin, 2016; Robinne et al., 2016). Whilst the global area burned declined by ~20% over the last two decades mainly due to agricultural expansion (Andela et al., 2017), many areas critical for water supply are exposed to increasing fire risk (Doerr & Santin, 2016; Sankey et al., 2017). This is due to increases in fire weather severity (Flannigan et al., 2013) and extended fire season in many regions (Westerling, Hidalgo, Cayan, & Swetnam, 2006), as well as fuel build‐up due to fire suppression, afforestation, land abandonment, and a trend towards more extensive fires (Doerr & Santin, 2016).