Over the past few weeks we have been reminded once again of the critical links between water and public health. The residents of Flint, Michigan, have been exposed to water contaminated with lead. Residents now have no choice but to utilize bottled water for drinking, cooking, and washing. The economic costs of refitting the Flint water system so that the pipes no longer leech lead into the water supply are astronomical and the repair will take many months, but the potential long term health consequences are in human terms much worse. The community has, rightly, lost any trust it had in those in charge of ensuring that they are protected from environmental hazards, a key responsibility of government.

Unfortunately, although stark, the Flint example is not an isolated case. All over the world the disadvantaged and the less powerful are frequently exposed to the worse environmental conditions with direct and measurable consequences for their health. Access to clean and safe water is a prime example of a public health intervention with long-lasting effects on a long list of health outcomes, including among others the protection against infectious diseases, the promotion of the growth and development of children, the protection from toxic environmental exposures (like arsenic and lead), and even the promotion of schooling among girls.

And yet we do a terrible job of ensuring access to safe, clean water, especially among the most disadvantaged. It is estimated that worldwide 1 in 9 people have no access to safe drinking water and that nearly 3.5 million people die each year as a result of inadequate water, sanitation, and hygiene. The major sources of water pollution are from human settlements and from industrial and agricultural activities. Even today in 2016, a third of the world's population lacks access to sanitation. The World Economic Forum classified the water crisis as the #1 global risk based on its societal impact.

There are many public health stories involving water. The famous Broad Street pump story, one of the foundational stories—or perhaps myths—of epidemiology is but one example. The provision of water and sanitation is often mentioned as one of the key triumphs of public health in the 19th century. The fluoridation of water is often discussed as a prime example of the types of population interventions espoused by public health. Today, with the renewed discussion on building a culture of health and developing intersectoral and population approaches to improve health, we should remember that access to clean water is an excellent example of the best public health in action. It requires the engagement of many disciplines and sectors and it is the paradigm of a population-level policy that affects everyone. It impacts multiple health outcomes through multiple pathways. It has the potential to reduce health inequalities.

It is easy to forget when we open the tap to get a glass of water or turn on the shower, that we are benefiting from a major societal advance that has improved not only health but also quality of life for all of us dramatically. This is why the Flint case, especially occurring in a rich country like the United States, is so jarring. It is compounded by the fact that, as has been repeatedly documented by the environmental justice movement, the failure to protect the population from hazardous environments is especially common in socioeconomically disadvantaged and minority communities, not only in the United States, but also worldwide.

Sadly, lead in the water is likely not the only environmental problem in Flint (or in communities like Flint). Fifteen years ago, a law article used Flint as an example of an urban community subject to multiple hazardous environmental exposures and argued that the existing legal framework failed to account for the likely cumulative and interacting effects of multiple exposures.

Environmental injustice is not only about exposures to toxic substances (important as is this) but also about the many often subtle ways in which disadvantaged communities are repeatedly exposed to environments that are not conducive to good health, including things like limited access to healthy foods and pleasant public spaces, poor quality of housing, lack of well-maintained sidewalks, lack of safety, and even simply poor aesthetic quality and absence of trees and green spaces. Some of these health effects may be subtle, but they add up and potentiate each other, and likely contribute to the large social inequalities that we continue to see.

Hopefully the renewed discussion in the media on the links between environments and health and on the large social inequalities that are present in many environmental exposures will not only help Flint but also galvanize greater actions to promote public health through appropriate environmental protections for all.