One of the Americans who saw their hopes of owning a home shattered was Janice Johnson, a black single mother on welfare and living about as far from the lily-white suburbs as a person could get. She and her 8-year-old son had lived in a decaying apartment, in a building that had recently been condemned by city officials, in a working-class black neighborhood in Northeast Philadelphia.

Facing eviction, Ms. Johnson needed to quickly find a new place to live. Her mother told her of an apartment for rent in the same neighborhood. Instead the landlord suggested that she buy a house there through the new HUD program.

Ms. Johnson bought her first home in September 1970. But days after she moved in, the sewer line broke, spewing wastewater all over the basement floor. The electricity was sporadic and haphazard. There were holes in the foundation. The windows were nailed shut and inoperable. The floorboards in her dining room were so rotten, she feared her table would fall through the floor.

The crumbling structure of the house was not the wors­­­­­­­t of it.

The day before Halloween, Ms. Johnson’s son woke up to find a rat in his bed. Rats were everywhere, including in the kitchen and bathroom, entering the house through holes in the basement, where they made their nests.

She called the real estate agent who sold her the house to complain. He sent workmen out a couple of times, and they even patched the failing plaster in her dining room; but soon after, the agent reminded her that the problems in her house were “homeowner’s business.”

The details of Ms. Johnson’s woes come from a court case; it’s unclear how her story ends.

There were thousands of cases like hers from Memphis to Minneapolis and they made front-page news. The Chicago Tribune even won a Pulitzer Prize in 1975 for its coverage of this crisis. Generous government subsidies had helped the real estate and banking industries overcome their reluctance to sell and lend to African-Americans. But of course they never stopped believing blacks presented a threat to property values, perpetuating the real estate industry’s segregationist practices.

While the policies created by the Housing and Urban Development Act did not immediately change the practices or the beliefs within the real estate industry — or among agents working for the Federal Housing Administration — it did allow for the participation of broader networks of real estate operatives and lenders that circulated billions of new dollars throughout the urban housing market.