When it comes to water, you’d think the cities of the Great Lakes would be the envy of the country. In a time of scorching drought and climate change, the northern coast is a place of abundance. The lakes hold an astounding 84 percent of all the surface freshwater in North America.

But even here, we struggle to deliver safe, affordable drinking water to millions of people, often communities of color. Throughout the region, these low-income neighborhoods face high water bills, contamination risks and large-scale shut-offs — all the manifestation of a history that many would like to forget. The “separate but equal” policies of the 20th century are still with us — and they explain why communities cannot take safe drinking water for granted, even amid the magnificent Great Lakes.

This year in Detroit, a city with a 35 percent poverty rate, 11,800 households had their water shut off for unpaid bills as of August. This is down from a peak of 44,000 shut-offs in 2014, but it is an alarming annual tradition that puts both personal and public health at risk.

And Chicago, once bold enough to reverse the flow of its namesake river in search of clean drinking water, hasn’t summoned the political will to deal with the lead pipes in its water system. With 385,000 of them, Chicago has more than any other city, causing alarming rates of households to be exposed to unsafe lead levels, a Chicago Tribune analysis found last year. Such pipes were mandatory until 1986, even though their toxic effect on water has been observed for more than a century. A long-term fix is elusive: Last spring, a judge threw out a class-action lawsuit that would have required the city to replace the pipes, even as he acknowledged that they contaminated the water, though an appeals court is forcing another look.

And then there is the water crisis in Flint, Mich. The mishandling of the city’s water was deadly, resulting in not only lead leaching from the pipes, but also bacterial contamination, a spike in a carcinogenic disinfection byproduct and a two-year outbreak of Legionnaires’ disease that sickened about 90 people and killed 12 — at least.

We built our cities out of lead. The underground network of pipes established the shape of our rising urban centers and isn’t easily dismantled. All pipes made of this neurotoxin, about 6 million nationwide, pose a risk. Across the country — including Newark, which is now under a federal order to deliver bottled water to residents — people of color struggle the most. An analysis of data from the Environmental Protection Agency showed that tens of millions of Americans are exposed to contaminated water, especially in communities that are poor and nonwhite.

During the 20th century, the Great Lakes cities that hummed with industry were beacons that enticed scores of African American migrants from the South to come in search of a better life. But there were limits. Redlining and other discriminatory practices denied new arrivals access to most properties and neighborhoods. The housing system worked in such a way that a home became less valuable the second a black owner signed its papers.

Fair housing and school desegregation laws were aimed at righting the inequality, but they also fueled an exodus of upper- and middle-class whites from core cities. Vacancy scarred places such as Detroit, Milwaukee and Gary, Ind., even as a widening circle of wealth surrounded them. In Flint, the U.S. Census marked its first population slip in 1970, two years after voters approved a groundbreaking fair-housing ordinance. By the time the Flint water crisis began in 2014, the population had shrunk from 200,000 to 98,900. About 57 percent are African Americans.

Shrinking cities have fewer ratepayers to maintain water systems designed to serve populations up to twice their current size, along with industries that have moved elsewhere. The oversized infrastructure is also aging, making its upkeep expensive. Deferred maintenance results in vast amounts of lost water through leaks and breaks.

Because of this, residents pay water bills that are often considerably higher than the rest of the country. Certain inner-ring communities in Chicago, for example, pay 20 percent more for their water than residents in other, whiter suburbs, even though they all draw their supply from Lake Michigan.

Environmental disasters don’t solely affect people of color. But the higher probability of them is in the DNA of segregation. That’s the logical outcome of concentrated vulnerability. We built disinvestment and exclusion into the bones of our cities as surely as we installed lead pipes, and their legacy is just as poisonous. Infrastructure inequality is passed down through the generations. The only cure is inclusion.

It isn’t all dire. Two Midwest cities — Madison, Wis., and Lansing, Mich. — are pioneers in carrying out a wholesale removal of lead lines in their systems, creating national models for how it can be done. And, chastened by what happened in Flint, the state of Michigan enacted tougher rules for lead in drinking water.

But until we reckon with our inherited, self-perpetuating legacy of segregation, we will not have environmental justice in America.

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