I first became interested in clean water initiatives while I was in Indonesia in July 2013. Before that I was aware of the issue, but seeing its effects in person had a much bigger impact on my motivation to take action about it.
There has been a lot of progress made in this area because of global health initiatives such as the Millennium, and later the Sustainable, Development Goals set forward by the United Nations. Since 1990, it is estimated that "2.6 billion people have gained access to an improved drinking water source" (WHO, 2015). This means that 91% of the world uses an improved drinking water source (WHO, 2015). However, that still leaves over 663 million people who lack access to clean drinking water (WHO, 2015).
The impact of contaminated drinking water goes far beyond short term sickness. Illnesses that we see as inconvenient but nonthreatening in the United States, like diarrhea, are sometimes fatal when you do not have clean drinking water to re-hydrate with. It is estimated that 2,200 children under 5 years old die daily because of diarrheal diseases (CDC, 2016).
Beyond access to clean drinking water, it is extremely important to also have access to improved sanitation. While poor health from water-borne illnesses contributes to school absences, it has been found that 20% of girls of primary-school age are not in school (CDC, 2016) possibly because it is their responsibility to collect water for the family or because there is not a latrine at school for them to use when they begin menstruation.
As you can see, access to clean drinking water and improved sanitation is extremely important for better health and more opportunities.
World Health Organization information: http://apps.who.int/iris/bitstream/10665/177752/1/9789241509145_eng.pdf?ua=1
Centers for Disease Control information: https://www.cdc.gov/healthywater/global/wash_statistics.html