Personal measures against COVID-19 infection, such as hand-washing and wearing protective clothing, are redundant without proper sanitation and a reliable water supply. As future pandemics become more likely, we urge political leaders, the global financial community and international agencies to accelerate funding to tackle the issue of water security.

The pandemic has exposed huge inequalities in water security, with more than 2 billion people, half of schools, and one-quarter of health-care facilities lacking a basic water or sanitation service (see

Among those most at risk are women and girls in low-income countries, who bear the burden of water collection; people with disabilities; and people living in remote rural locations or in overcrowded settlements and refugee camps (see Nature 581, 18; 2020).

The world is nowhere near achieving the sixth United Nations Sustainable Development Goal of ‘clean water and sanitation for all’ (R. Naidoo and B. Fisher Nature 583, 198–201; 2020). COVID-19 has underlined how failure to provide water security to some compromises the public health and economic prospects of all. The UN secretary-general stated that “We are only as strong as the weakest health system.” In turn, the world’s health system is only as strong as its least water-secure region.