A government-based tax incentive boosted sales through the spring, but the market dropped off sharply through the summer.
High unemployment and tight credit have worked against record-low mortgage rates, holding sales at a tepid pace.
The seasonally adjusted estimate of new houses for sale at the end of September was 204,000, representing a supply of eight months at the current sales rate.
The median sales price of new houses sold in September 2010 was $223,800, up 3 percent from a year ago. The average sales price was $257,500.