The BSA says continued uncertainty has continued to push consumers away from the housing market.
Building society gross lending amounted to £2.7bn in August compared to £4.3bn for the same period in 2007.
Net lending by building societies was down £809m to negative £38m compared to £771m in August 2007.
Andrew Gall, business economist at the BSA, says: “Activity in the housing market remains depressed so although the figures for both net approvals and net lending are better than for last month, they still remain low.
“With the Land Registry data showing a 4.6% annual drop in property prices, and the BSA’s own Property Tracker survey showing that more than half of people consider the prospect of future falls in house prices a barrier to house purchase, it is hardly surprising that demand for mortgages is so low.”