Tenants saddled with months of back rent were facing the end of the federal eviction moratorium on Saturday, a move that could lead to millions being forced from their homes as the highly contagious Delta coronavirus variant spreads.

The Biden administration said on Thursday it would allow the nationwide ban to expire, saying it wanted to extend it but its hands were tied after the supreme court signaled in June that it wouldn’t be extended beyond the end of July without congressional action.

House lawmakers on Friday failed to pass a bill to extend the moratorium even a few months. Some Democrats had wanted it extended until the end of the year.

“August is going to be a rough month because a lot of people will be displaced from their homes,” said Jeffrey Hearne, director of litigation for Legal Services of Greater Miami. “It will be at numbers we haven’t seen before. There are a lot of people who are protected by the … moratorium.”

The moratorium, put in place by the Centers for Disease Control and Prevention (CDC) in September, helped keep 2 million people in their homes as the pandemic battered the economy, according to the Princeton University’s Eviction Lab.

Eviction moratoriums will remain in place in New York, New Jersey, Maryland, Illinois, California and Washington DC, until they expire later this year.

Elsewhere, evictions could begin on Monday, leading to a years’ worth of evictions over several weeks and ushering in the worst housing crisis since the last major recession, in 2008.

Roxanne Schaefer, suffering from health issues including respiratory problems and a bone disorder, is one of the millions fearing homelessness. In a rundown, sparsely furnished Rhode Island apartment she shares with her girlfriend, brother, a dog and a kitten, the 38-year-old is $3,000 behind on her $995 monthly rent after her girlfriend lost her dishwasher job.

Boxes filled with possessions were behind a couch in the apartment, which Schaeffer says is infested with mice and cockroaches and even has squirrels in her bedroom.

The landlord, who tried to evict her in January, has refused to take federal rental assistance so the only thing preventing him changing the locks and evicting her is the CDC moratorium. Her $800 monthly disability check won’t pay for a new apartment. She only has $1,000 in savings.

“I got anxiety. I’m nervous. I can’t sleep,” said Schaefer, of West Warwick. “If he does, you know, I lose everything, and I’ll have nothing. I’ll be homeless.”

More than 15 million people live in households that owe as much as $20bn to landlords, according to the Aspen Institute. As of 5 July, roughly 3.6 million people in the US said they faced eviction in the next two months, according to the US Census Bureau’s Household Pulse Survey.

Parts of the South and other regions with weaker tenant protections will likely see the largest spikes and communities of color, where vaccination rates are sometimes lower, will be hit hardest. But advocates say this crisis is likely to have a wider impact than pre-pandemic evictions, reaching suburban and rural areas and working families.

“I know personally many of the people evicted are people who worked before, who never had issues,” said Kristen Randall, a constable in Pima county, Arizona, who will be responsible for carrying out evictions starting on Monday.

“These are people who already tried to find new housing, a new apartment or move in with families,” she said. “I know quite a few of them plan on staying in their cars or are looking at trying to make reservations at local shelters. But because of the pandemic, our shelter space has been more limited.

“We are going to see a higher proportion of people go to the streets than we normally see. That is unfortunate.”

The crisis will get worse in September when foreclosure proceedings are expected to begin. An estimated 1.75 million homeowners roughly 3.5% of all homes are in some sort of forbearance plan with their banks, according to the Mortgage Bankers Association. By comparison, about 10 million homeowners lost their homes to foreclosure after the housing bubble burst in 2008.

The Biden administration had hoped historic amounts of rental assistance allocated by Congress in December and March would help avert an eviction crisis. But so far, only about $3bn of the first tranche of $25bn had been distributed through June by states and localities. Another $21.5bn will go to the states. Some states like New York have distributed almost nothing. Others have only approved a few million dollars.

“We are on the brink of catastrophic levels of housing displacement across the country that will only increase the immediate threat to public health,” said Emily Benfer, a law professor at Wake Forest University and the chair of the American Bar Association’s Task Force on Eviction, Housing Stability and Equity.

Some places will see a spike in people being evicted in the coming days, while other jurisdictions will see evictions over several months.

“It’s almost unfathomable. We are on the precipice of a nationwide eviction crisis that is entirely preventable with more time to distribute rental assistance,” Benfer said. “The eviction moratorium is the only thing standing between millions of tenants and eviction while rental assistance applications are pending. When that essential public health tool ends on Saturday, just as the delta variant surges, the situation will become dire.”