Dr Charles is an environmental engineer who focuses on improving access to safe drinking water and sanitation. Throughout her career she has worked on issues related to water and sanitation that include: public health, environmental fate and transport of pathogens, impacts of climate change on access, and barriers to adequate sanitation in informal settlements. Her work has been funded by the World Health Organization, DFID, UK Research Councils (NERC/ESRC), and the Bill & Melinda Gates Foundation, and includes work in Kenya, Rwanda, and Uganda. Dr Charles undertook her PhD on a risk-based approach to management of decentralised wastewater treatment systems in Sydney's drinking water catchments in Australia. She joined the University of Oxford in 2013 having previously been a lecturer at the University of Surrey.