Chicago suburbs posted big year-over-year gains in the third quarter of 2011.

Detached single-family homes sales in suburban Chicago rose more than 20 percent (and attached 30 percent) in the third quarter of 2011 compared to the same period a year ago, according to statistics released by the Mainstreet Organization of Realtors (MORe).

Suburban Chicago includes all of DuPage and Lake counties, suburban Cook County and portions of Will County. Communities with particularly strong increases included Bartlett, with an 86 percent increase, Evergreen Park at 43 percent, Orland Park at 48 percent, Wheaton at 57 percent and Lombard at an incredible 109 percent.

Tom Krettler, the co-president of MORe, said the current market’s incredible affordability is driving sales.

“There are so many deals out there for the picking right now that it’s unbelievable,” Krettler said. “If you’re financially able, it’s a great time to upgrade. Many investors are also snatching up homes and using the strong rental market to generate instant cash flow.”

Jack Persin, the fellow co-president of MORe, said an increase in housing activity is a good thing for everyone.

“Recovery in the housing market will help our overall economic recovery,” Persin said. “We’re seeing some positive movement, but we still need the federal government to do all it can to support homeowners.”