A total of 79% of mortgage holders and 81% of tenants are anxious about the issue, according to the Which? consumer insight tracker.
Alarmingly, this is the highest level since the survey began in 2013.
Rocio Concha, Which? director of policy, said: “Although UK inflation is slowly starting to fall, these record levels of worry about housing costs and the looming threat of higher interest rates later this month show that, for many people, the cost-of- living crisis is far from over.”
Neil Kadagathur, co-founder and chief executive of financial experts Creditspring, said: “With savings pots dwindling and mortgage costs spiking, millions of households are concerned about how they’re going to make ends meet each month.
“Renters also face huge disruption – 20% are expecting to have to move home as rents soar to unaffordable levels as landlords pass on the rising costs to tenants.”
There has been a steady increase in housing cost concern among renters over the past two years, with 62% saying they were worried in August 2021.
Fears have risen even faster for mortgage holders due to high interest rates, which have been climbing steeply since December 2021 when a series of hikes began.
Yesterday, it was reported that the average UK house price dropped by 4.6% in August, falling at the fastest rate since 2009.
The average value was £14,000 less than a year earlier, said the Halifax.