Flooding in Albany Park, Chicago, Illinois, 2008. Photographer: Chuck Berman/Chicago Tribune

Redlined, Now Flooding

Maps of historic housing discrimination show how neighborhoods that suffered redlining in the 1930s face a far higher risk of flooding today.

March 15, 2021, 5:00 AM EDT

Flooding is a rising threat across the U.S., with homeowners facing as much as $19 billion in damages every year. What puts a neighborhood at high risk for flooding? Geography is key, but new data reveal another factor that can be determinative, too: race.

Contemporary maps for flood risk overlap in striking ways with New Deal–era maps used by the federal government to assess risk for mortgage lending. When appraisers mapped cities for the federal Homeowners’ Loan Corporation in the 1930s, they assigned grades to neighborhoods based on several factors, race high among them. Black and immigrant neighborhoods were deemed undesirable, marked by yellow or red lines designating these areas “declining” or “hazardous”—a racist practice known as redlining.

These historically redlined neighborhoods suffer a far higher risk of flooding today, according to new research from Redfin, the Seattle-based real-estate brokerage.

Using flood risk data from the nonprofit First Street Foundation and redlining maps from the University of Richmond’s Mapping Inequality project, Redfin assessed racial disparities in flood risk across dozens of major metro areas.

Consider Sacramento. The California capital region, with a population of more than 2 million, had the highest racial flood risk disparity in Redfin’s analysis.

For Sacramento, the greatest risk for flooding comes not from the city’s twin rivers but from its many creeks and distributaries.

In the 1930s, assessors praised Sacramento’s greenlined neighborhoods for their social homogeneity. Just one-third of the households in these areas today are non-white.

Appraisers redlined areas with racial minorities as undesirable for mortgage lending. Nearly half of the households in these neighborhoods are non-white.

Creeks in Sacramento have a high flood risk after strong downpours, with the highest risk in historically redlined neighborhoods.

Note: Researchers at Redfin measured the flood risk in A- or B-graded neighborhoods (greenlined in these maps) versus C- or D-graded neighborhoods (redlined).

Across 38 major U.S. metros, more than $107 billion worth of homes at high risk for flooding were located in historically redlined (and yellowlined) neighborhoods. That’s 25% more than the value of homes at high flood risk located in parts of the city deemed desirable—that is, white neighborhoods.

Put another way, 8.4% of homes in historically redlined neighborhoods face high flood risk nationwide, compared with 6.9% of homes in historically greenlined neighborhoods. These patterns reflect disparities in development compounded by decades of disinvestment.

Gardenland, for example, is a diverse, working-class neighborhood located along Steelhead Creek in North Sacramento. It has a high risk for flooding, at least when California isn’t under drought conditions. In 1938, Gardenland earned a C grade, or “definitely declining.” Although the development of Gardenland had only just begun in the 1930s, appraisers noted a confluence of demographic and infrastructure factors as justifying a dismal outlook: the standing water that followed hard rains, a lack of paved streets or sewers and a heterogeneous population described as Mexican.

“You’d see references about decaying infrastructure, water being stagnant after rainfall or sewer problems,” says Schery Bokhari, senior economist for Redfin, referring to redlining maps. “By penciling that in, they created this cycle of underinvestment in those communities.”

Water cresting the south bank of the American River in Sacramento, California, 2017. Photographer: Gary Coronado/Los Angeles Times via Getty Images

Redlining maps make for bracing reading. Surveyors made explicit recommendations for mortgage lending based on race and immigration that helped to entrench de facto segregation, condemning entire areas as slums. “Low grade Italian population of questionable occupation and income,” reads the entry for a redlined part of Brooklyn near Bensonhurst in New York. “Very little likelihood of improvement.”

Of Manhattan’s Lower East Side, the redlining map says, “It is inconceivable that it can get any worse.”

Flood risk today isn’t race blind: Investments in sewers, levees and other infrastructure rescued some neighborhoods from flooding but left others behind. Systemic factors that guided investment exposed Black and Brown households to more severe flood risk. A vicious cycle of segregation and disinvestment reinforced the linkage between race and flood risk.

This pattern makes flooding a matter of environmental justice: Much like asthma, lead exposure, traffic fatalities and other public health threats, flooding disproportionately impacts minority neighborhoods.

Sacramento’s disparity is alarming: More than 1 in 5 homes (21.6%) in the city’s formerly redlined neighborhoods face a high risk of flooding today. In Sacramento’s formerly greenlined areas, just 11.8% of homes face the same risk. That 9.8% disparity in flood risk is the largest among any of the cities analyzed by Redfin. But it isn’t the only way to measure this dynamic. In terms of property value, the gap is greater elsewhere.

In Chicago, the total value of homes at high flood risk is $3.6 billion in greenlined neighborhoods versus $19.7 billion in redlined neighborhood, a difference of more than $16 billion. For New York City, the delta is $12.6 billion.

Gentrification has changed the demographic profile of some places at risk: Logan Square, an historically redlined neighborhood in Chicago prone to basement flooding, has seen housing prices rise steadily over the last decades. Still, formerly redlined neighborhoods such as Bronzeville overwhelmingly pay the price: Nearly 90% of flood damage payments go to households in communities of color, according to a 2019 study.

Flood risk keeps increasing as well: Chicago ranks just behind the storm-ravaged coasts of New York, Louisiana and Texas for flood losses. While the city has targeted the trendy Milwaukee Avenue corridor for rain barrels, backyard rain gardens and other improvements, in many neighborhoods, it falls on bungalow owners to keep stormwater out of their basements.

A few cities buck the trend in segregated flood risk disparities. In Miami, the areas deemed most desirable have always been the city’s fantastic beaches. Today, these beaches represent the glitziest neighborhoods in the city, but they are at severe risk of flooding as sea levels rise due to climate change.

A huge share of households in Miami’s historically greenlined beach areas (53.9%) are at high risk of flooding, representing a whopping $22.7 billion in home values—much more than the share in formerly redlined areas (34.2% at $7.0 billion). The same applies to waterfront areas in Jacksonville and Tampa as well as Virginia Beach, Virginia. That doesn’t mean flooding in these places won’t adversely impact communities of color. As some developers retreat from the flood-prone coasts, many poorer inland communities fear displacement in the form of “climate gentrification.” And in the diverse Miami region, even many coastal neighborhoods are majority-minority.

“With the exception of some of the beaches across the country, in the cities we analyze, generally speaking—and especially in Sacramento, Boston, New York, Chicago and Detroit—there was a bigger share of homes facing high flood risk in these formerly red- and yellowlined areas than in areas that were marked as best, where all the nonminorities ended up living,” Bokhari says.

After some of the worst flash flooding in decades, vehicles sit submerged in water along I-75 outside of Detroit, Michigan, 2014. Photographer: Joshua Lott/Getty Images

One thing that the cities with racial disparities in flood risk have in common: They are still highly segregated today. In 9 of the 10 cities with a larger share of formerly redlined homes at risk for flooding, the share of nonwhite households in those redlined neighborhoods is also greater. In Newark and Camden in New Jersey, the disproportionate impact on minorities is pronounced. The same holds for Indianapolis, Seattle and Portland, Oregon.

Two cities stand out in this analysis: Detroit and Baltimore are the only places where the share of Black and Brown households living in formerly greenlined areas is higher than the share of minorities living in formerly redlined neighborhoods. In these majority-minority cities, communities of color face high flood risk across these two categories of neighborhoods.

Today, in Sacramento, flooding is not necessarily the first item on the agenda for advocates fighting for environmental justice—if only because the years-long drought in California makes flooding less common.

Access to creeks is another matter, according to Nailah Pope-Harden, state policy manager for the nonprofit ClimatePlan and founder of the Sacramento Environmental Justice Collaborative Governance Committee, a new quasi-official advisory group for the city. These creeks may be associated with a higher risk of flooding, but for advocates, they are also overlooked resources.

“It’s almost unheard of, a resource that was just completely taken for granted by the city of Sacramento, by county folks and by the people who lived in the neighborhoods themselves,” Pope-Harden says. Her work, she says, is “all about ensuring that communities have equal access to healthy environments.”

Pope-Harden says that communities in South Sacramento are looking to play a role in the Morrison Creek Revitalization Project, an ecological and infrastructure development effort. Activists want to revamp a half-mile portion of the creek to replace vacant lots running along the creek with publicly accessible parks.

Walking through a flooded street caused by seasonal high tides and rising sea levels in Miami Beach, Florida, 2015. Photographer: Joe Raedle/Getty Images

Such an effort along Morrison Creek might also help to alleviate flooding for surrounding neighborhoods. For the time being, segregated flood risk runs behind other environmental justice priorities, namely severe disparities in air quality. One reason flooding might not be a focus yet in Sacramento is that the full scope of the potential costs and lack of government preparation is only just coming to light.

As the Redfin analysis shows, any effort to improve data on flood risk will need to examine equity. The goal is to better understand who will ultimately pay the costs and how to mitigate risk for the future.

“Severe storms and hurricanes have a disproportionate effect on minorities in terms of damage done, life lost, and the amount of money that gets reimbursed,” Bokhari says. “This project was done to look back at the legacy of redlining and link it to the outcomes we see today.”

Redlined, Now Flooding

Maps of historic housing discrimination show how neighborhoods that suffered redlining in the 1930s face a far higher risk of flooding today.

Separate and Unequal

New York City

Chicago

Miami

Detroit