One in three families in England could not pay their rent or mortgage for more than a month if they lost their job, a study for the charity Shelter suggests.
High housing costs and a lack of personal savings are cited by the charity as reasons for this.
The online survey by pollsters YouGov in July questioned 1,581 people in working families with children.
"Strong protections" are in place for "those who fall on difficult times," a government spokesman commented.
"We are continuing to spend around £90bn a year on working age benefits to ensure a strong safety net for the most vulnerable.
"And for those who do fall on difficult times, there are strong protections in place to guard against the threat of homelessness, and ensure we don't return to the bad old days when homelessness in England was nearly double what it is today."
The government said protections against homelessness included:
- protecting the £315m homelessness prevention funding for local authorities
- committing £139m to homeless programmes until 2020
- spending a further £100m on accommodation support funding
- doubling the housing budget and investing £8bn to build 400,000 affordable homes
'A scary place to be'
Single mother-of-two Karen Lucas was made redundant from her job as a financial analyst and was out of work for almost two months.
Karen, from Basingstoke, said: "I lost my job in May, having been headhunted into the role and then told I wasn't needed after three months' probation.
"I had relocated and changed my plans to take up the role and was then left with £1,200 monthly rent to pay on just £73 per week jobseeker's allowance.
"I was able to cover one month's rent from money I had in the bank - but even that was a struggle.
"I had to apply for discretionary housing benefit and move my debts on to a payment plan, which will now affect all my future credit rating."
Karen has now found a new job, but is earning considerably less than before and making ends meet is a struggle.
"The effects of losing my job and being out of work for seven weeks will give me a headache in dealing with it for a good number of years to come," she added.
The online YouGov survey questioned 8,381 adults, including 1,581 members of working families with children.
It concluded that 37% of such families would be unable to cover their housing costs for more than one month with no job, while 23% said they would be unable to pay their housing costs at all.
Some 48% of families in the survey named the cost of housing as the biggest drain on their budget, the charity reported.
"These figures are a stark reminder that sky-high housing costs are leaving millions of working families stretched to breaking point, and barely scraping by from one pay cheque to the next," Shelter chief executive Campbell Robb said.
Mr Robb said the government had a "real chance to show working families they're on their side, by protecting and improving our welfare safety net".