Sonoma County’s median home price shot up in August to $385,500, an 11-percent increase from July as buyers purchased a larger share of properties priced between $400,000 and $800,000.

The median price for August was the highest for any month in nearly three years, according to The Press Democrat’s monthly housing report compiled by Pacific Union International Vice President Rick Laws.

Buyers purchased 520 single-family homes last month, an 11-percent increase from a year earlier.

To date this year, 3,665 county homes have been sold, a 21-percent increase from 2011 and the most sales in seven years.

Short sales and foreclosures last month made up 30 percent of all sales, the lowest level in at least four years. Short sales are properties being offered for less than the amount owed on the mortgage.

Homes selling between $400,000 and $800,000 made up 38 percent of all sales, the biggest share for any month in nearly three years.

That means we’re finally getting people who are moving up and many of these buyers are selling a starter home and purchasing a more expensive property.

The market still has a large share of distressed properties, but it’s far better than nearly four years ago when three out of every four sales involved a short sale or foreclosure.

The county’s median price still remains far below its August 2005 peak of $619,000. And more 28,000 county homes, or 27 percent of all homeowners with mortgages, owe more than their homes are worth, according to a report released Wednesday by CoreLogic.

But agents say the market has rebounded off its lowest point in the downturn of $305,000 in February 2009.

Part of the reason for the rise in prices is that fewer homes are available for sale this year. August ended with an inventory of less than 1,000 homes for sale, about half the amount of a year earlier.