The median price of single-family homes in Massachusetts fell 12.3 percent in July, marking the sharpest decline in monthly home prices since The Warren Group, Banker & Tradesman’s parent company, began tracking the housing market in 1987.

The median price for single-family homes sold in July dropped to $320,000 from $365,000 in July 2007, according to The Warren Group.  The year-to-date median price is $316,000, a 9.7 percent decline from $350,000 a year ago. Prices have decreased in every county this year except for Nantucket, where they have flattened.

“The good news in July was that home sales didn’t decline as precipitously as they have in the previous six months of the year. Unfortunately, prices dipped even more than they did this past April, when prices were 12 percent lower than a year earlier. The drop is a dramatic turnaround from five to six years ago when prices were escalating by double-digit percentages,” said Timothy Warren Jr., CEO of The Warren Group. “Foreclosure activity has certainly dragged down home prices and will continue to affect the overall market.”

Sales of single-family homes also continued to drop in July, slipping 6.4 percent to 4,495 from 4,800 in July 2007. It was the only month this year that monthly sales haven’t declined by double-digit percentages. Meanwhile, year-to-date sales are down 16.9 percent, to 22,976 from 27,651.

While home sales in July have fallen in most parts of the state, sales climbed in Barnstable, Berkshire, Dukes, Essex and Franklin counties.

Condo sales continued to fall by double-digit percentages, but less dramatically than previous months this year. A total of 2,236 condos traded hands in July, down 12.5 percent from the 2,556 sales recorded a year earlier. Condo sales have fallen by more than 20 percent for eight consecutive months. Year-to-date sales have plummeted 25.9 percent to 12,076 from 16,289. 

Condominium prices haven’t retreated as much as single-family home prices. The median condo price dipped 2.5 percent to $287,750 from $295,250 in July 2007. Year-to-date condo prices have remained relatively flat at $279,700 compared to $282,000 a year ago – representing about a 1 percent decline.