Around 2.5 to 3 billion people worldwide don’t have access to clean water. There are at least another 1.5 billion in developed countries who may have access to clean water but don’t trust its quality.
A number of widely publicised events about unreliable water services in countries have added to this mistrust. Seventeen years ago Walkerton in Canada had the country’s worst e.coli contamination of domestic water supply. It resulted in seven deaths and 2300 illnesses. In 2014, Flint, Michigan, USA, changed its source of water supply to Flint River. This corrosive source