On average, every US dollar invested in water and sanitation provides an economic return of eight US dollars.
Investment in safe drinking water and sanitation contributes to economic growth. For each $1 invested, the World Health Organization (WHO) estimates returns of $3 - $34, depending on the region and technology.
Those who lack access to water are not a homogeneously poor group. Nearly 66% of people who lack safe drinking water live on less than $2 a day, while 33% on less than $1 a day.
An evaluation of major sanitation programs in six countries by the World Bank revealed households tend to be the primary investors in household on-site sanitation facilities. If provided access to credit, poor households were found to be able to allocate a significant portion of their income to sanitation investments. Access to credit was found to play a significant role in triggering household sanitation investments.
People living in informal settlements (i.e. slums) often pay 5-10 times more per liter of water than wealthy people living in the same city.