New York City is experiencing its worst housing crisis in decades, and a new crisis is building. 

The median rent in the city’s most expensive neighborhood, Flatbush, has soared more than 400% in the past four years to more than $1,500 a month, according to Zillow. 

There are more than 100,000 people living in apartments that have been underwater for years. 

While many of the units in Flatbush are for rent, a growing number are occupied by long-term renters who rent out rooms to guests. 

Zillow says there are more people living underwater than at any point in history. 

It’s a trend that could accelerate if Congress doesn’t do anything about the situation. 

“It’s going to be a vicious cycle for the foreseeable future,” says Matt Larkin, vice president of housing policy at the Urban Institute. 

Larkin, who helped draft a bill last year that would have required a 20% tax on underwater properties, says Congress should “focus on a broader approach to protecting underwater renters” instead of passing a law that will only impact those who are already underwater. 

For many renters, a rental loss isn’t even the biggest issue, he says. 

People who lost their homes are facing a “burden” of paying rent for the next five years.

Many others have to worry about getting food on the table for the same amount of time. 

But for people who are living in a rental, the most pressing issue is the inability to pay for utilities or the ability to get to and from work. 

This has left renters feeling “uncomfortable and isolated,” Larkin says.

That’s why it’s crucial that Congress address this problem and protect the rights of renters, he adds. 

Housing is one of the most vulnerable sectors in the economy, and lawmakers are under pressure to make housing affordable for everyone. 

At the same time, the Affordable Care Act has brought new life to the housing market, and it’s making it easier for millions of people to afford housing. 

If Congress doesn.t act, there’s a growing possibility that a new wave of displacement will take place, says Larkin. 

That’s why we need legislation to protect renters. 

We need a housing crisis to be addressed and addressed quickly, Larkin argues. 

So what can Congress do? 

“There are a lot of steps that can be taken to protect and help underwater renters,” he says, noting that the law should include a 30% tax increase on underwater property. 

Another option is for Congress to consider “the need for a comprehensive strategy to address this crisis,” he adds, which would include “raising the minimum wage, requiring employers to pay their employees a living wage, and providing subsidies to renters who need housing to stay afloat.” 

But lawmakers aren’t the only ones facing a housing crunch. 

On the East Coast, the housing crisis has gotten worse, according the National Low Income Housing Coalition. 

They say the median rent for a one-bedroom apartment in Brooklyn, where they live, is now more than 3,000% higher than it was a year ago. 

In the Washington, D.C., metro area, the median rental costs more than double the median income for renters.

And in Seattle, a median rent of more than 5,000 percent is more than 40% higher. 

Even if Congress does act on these issues, Larkins says, it won’t be enough. 

His group is calling on the House to pass a bill that includes a 10% tax hike on underwater housing, which could provide a lifeline for renters struggling with rent. 

What can Congress and the administration do to help renters? 

The administration could provide rental subsidies, the coalition argues, by making sure that those who earn below the federal poverty line receive housing vouchers. 

Or the Department of Housing and Urban Development could expand the availability of subsidized rental assistance to people who need it, the group says.