The LSL Property Services index says the figure matches the peak in tenants looking for new homes to rent.
The firm, which owns Your Move and Reeds Rains, said rents increased by 2.4% in the year to August in England and Wales.
Rents now cost £3 a month more than the previous record of £758 which was set in October 2013. The figures reveal that rents increased by 1.1% between July and August.
Buy to let investors enjoy bumper returns
The index also reveals how buy to let investors have grown in number in the past year with capital growth and rental increases helping to deliver a return of nearly 13%.
David Newnes, a director at LSL, said: “Already 2014 has been like no other year and the rental market provides flexibility which it does well.”
He said that rents peaked at this time of year because it is when people move for new opportunities and careers.
Rents rise in seven out of 10 regions
A closer examination of the figures reveal that seven of the 10 regions in England and Wales are now more expensive for tenants than they were a year ago.
Leading the pack are rents in the South West, which rose by 3.5% over the year, followed by the South East with 3.4% and the North West which have seen a 3.3% rise.
However, London saw annual rent increases of 3% to miss out on a top three placing while rents for the North East are down by 1.6%.
Landlords in the West Midlands and Wales also saw drops in rent of 0.4% and 0.1%.
LSL says the actual return being enjoyed by BTL investors is 12.7% for the year with the average being £8,233 in rent and £13,066 in capital gains.
Lenders cut by to let borrowing rates
Meanwhile, buy to let landlord loan rates have been slashed by a number of High Street lenders bidding to cash in on the growth in BTL investment.
The market is booming with news that BTL investors are seeing ever higher returns (see above article) and lenders predict a rise in mortgage rates is some way off yet.
The best deal announced this week is from Leeds Building Society which has cut a two-year fixed deal from 3.49% to 3.09% with a 40% deposit.
Others that have also reduced fixed BTL mortgage rates include Virgin Money, Accord and Santander.
