Phillip Young, a resident from Jackson, Mississippi, takes a break while helping volunteers distribute bottles of water during the city's water infrastructure crisis on August 31, 2022.
CNN  — 

When torrential rainfall in August 2022 pushed the Pearl River in Mississippi to surge well beyond its banks, floodwaters spilled into the suburbs of Jackson and led an already-hobbled water treatment plant to fail.

It was the final stroke in what experts described as a yearslong issue in the making, which eventually left tens of thousands of residents in the city without clean drinking water for weeks.

What happened in Jackson, experts say, is a bellwether for what’s to come if America continues to kick the can down the road in addressing its aging and crumbling water infrastructure. The climate crisis threatens to make those issues even more pressing.

When sea levels rise, summers become hotter or heavy rains lead to more flooding, the country’s water infrastructure – largely built last century and only designed to last roughly 75 years – will be more strained than ever, threatening a system vital to human life.

At the rate our climate is changing, America’s water infrastructure is not equipped to handle the challenges to come, said Erik Olson, the senior strategic director for health and food with the Natural Resources Defense Council.

“America’s water system relies on last century’s infrastructure that often can’t protect our health from hazardous contaminants,” Olson told CNN. “And our outdated system is completely unprepared for this century’s challenges of intense heat, drought and flooding.”

The American Society of Civil Engineers gave America’s drinking water infrastructure a C-minus in its 2021 report card. And climate change-fueled extreme weather disasters promises a gauntlet of even tougher tests.

The 2021 infrastructure legislation signed by President Joe Biden includes about $30 billion for drinking water, and the 2022 Inflation Reduction Act another $550 million for water infrastructure. But experts say those figures are not enough to make up for decades of disinvestment and mismanagement across the country.

In Jackson alone, it could cost $1 billion to $2 billion to repair the water system, and the water industry estimates that the total nationwide costs will top $1 trillion. “Federal investments account for just a few percent of the total needs,” Olson said.

To better understand the issue, CNN examined five cities or regions across the country that show signs of vulnerability under a rapidly warming planet – from coastal flooding in New York to saltwater intrusion in California’s groundwater.

Buffalo, New York

Lake Erie water slams onto the shore during a winter storm on December 23, 2022, in Hamburg, New York.

Buffalo water officials don’t have to wonder too hard about its worst-case scenario. It basically happened last year.

A devastating winter storm dropped more than 50 inches of snow on the city in December, knocking out power, making roads impassable and killing 46 people in the area.

The high winds from the storm generated a phenomenon known as a “seiche,” in which water from the west end of Lake Erie near Toledo was pushed east, creating high water levels and coastal flooding in Buffalo.

The blizzard and seiche flooding threatened to knock out power to Buffalo’s water treatment plant, located precariously along Lake Erie. Thankfully, the plant has multiple backup sources, and the plant employees toughed out the storm, keeping the plant online and delivered clean water to residents. But Oluwole “OJ” McFoy, the general manager of the Buffalo Sewer Water Authority, said it was a “nightmare scenario” for the city and a warning of how rising water levels could impact its water infrastructure.

“(If) we don’t have power, we can’t do anything. And we’ve seen those high winds, especially those associated with many of these high lake levels, knock out power, and we’ve had to use our backup power as well,” he said. “Everything for us is just about being resilient, but those things cost money, and you have to make sure that as part of your capital expenditure that you’re building that resiliency into your system.”

The monster blizzard that killed dozens in the US over the Christmas weekend in 2022 crippled parts of New York state.

The non-profit organization Buffalo Niagara Waterkeeper has teamed up with the city on a study of the city’s coastal resiliency. Climate change has made the flooding issues worse in recent years, as the average water level has risen and the lake no longer completely freezes over in winter.

“That perfect storm – flooding, coastal storms, lack of ice coverage, fluctuating lake levels, erosion – all of that is being exacerbated from the effects of climate change,” said Kerrie Gallo, the deputy executive director of Buffalo Niagara Waterkeeper.

Prichard, Alabama

The Gulf Coast is no stranger to devastating storms. But in Gulf cities that aren’t as populous or well-invested in, a hurricane could trigger a water infrastructure crisis.

Residents of Prichard, Alabama, believe their city – a less than 10-minute drive from Mobile – could be “the next Jackson,” said Carletta Davis, president of the non-profit We Matter Eight Mile Community Association. From intensifying storms to leaking water lines that are never addressed, as well as racial injustice, the issues they face are multifold, she said.

Prichard’s infrastructure on average leaked 56% of the water coming in from reservoirs each month from April 2021 through November 2022, according to a report from the Alabama Department of Environmental Management.

“This water system has completely failed,” Davis told CNN.

“Hurricanes are one of our biggest threats, along with heavy rainfall, coastal erosion and flooding,” she said. “And when it rains, we have sewage overflows, buses can’t even get kids from school to their homes, and the streets are completely impassable.”

Semler Street resident Mack Robinson checks on his tornado-damaged home in 2012 in Prichard, Alabama.

Prichard is a predominantly Black and low-income city, and the historical legacy of disinvestment and racial injustice remains baked into the decisions made for the city’s residents, including repairing and upgrading its water systems, said Catherine Coleman Flowers, founder of the Center for Rural Enterprise and Environmental Justice.

“The problem we are seeing in Prichard is similar to the issues we see plaguing communities around the country,” Flowers told CNN. “Failing water and sanitation infrastructure that hasn’t been repaired in decades due to lack of funding and discriminatory distribution of public funds have led to issues that can spread diseases and threaten public health.”

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