San Diego's average home price hit $350,000 in September. That's an increase of more than 11 percent from the average price during the same month last year.
DataQuick tracks the region's home sales activity.
The firm found there are significantly fewer foreclosures on the market, and in affordable neighborhoods, fewer homes are for sale.
"One of the reasons sales have dipped, particularly in the more affordable neighborhoods, is they just don't have the inventory. There just aren't enough listings right now," said Andrew LaPage of DataQuick.
"Partly because so many people are upside dow, they owe more on the their mortgages than their homes are worth. So they couldn't sell if they wanted to. They are just sort of stuck until prices rise."
Home sales in the Southern California region fell in September, but not in San Diego.
Just over 3,200 homes changed hands last month here, and that was up about a hundred from a year ago.