About 4 billion people experience severe water shortages for at least one month a year and around 1.6 billion people - almost a quarter of the world's population - have problems accessing a clean, safe water supply, according to the United Nations.
While the UN's Sustainable Development Goals call for water and sanitation for all by 2030, the world body says water scarcity is increasing and more than half the world's population will be living in water-stressed regions by 2050.
"NGOs like to have their photographs taken with a shiny new hand pump ... then they walk away and it's handed over to communities to raise the funds to maintain these systems, to make sure that they're repaired. And if they're not?" she said.
"The research indicates at any one time one third of hand pumps across Sub-Saharan Africa are broken."
PHOTO EDITING MARIKA KOCHIASHVILI; WRITING STUART MCDILL and ALEX RICHARDSON, EDITING Mike Collette-White