The numbers aren’t as bad as two years ago but the sizable number of underwater mortgages in the Chicago region still present a problem for the housing market.

One-quarter of homes with a mortgage in the Chicago area, and almost 24 percent in Illinois, are “seriously” underwater, meaning homeowners owe at least 25 percent more on the loans than the property’s value, according to data released Thursday.

The report from RealtyTrac, which shows the percentage of underwater homeowners growing in most parts of the nation, helps explain why more homes are not coming on the market, despite the desires of would-be sellers. They simply don’t have the equity in their properties to be able to sell them unless they bring cash to the closing table or get approval from their lender for a short sale.

Also driving up the percentage of underwater borrowers is the slowing rate of appreciation that many housing markets are seeing, a trend that economists say is a return to more normalized boosts in housing prices. In the Chicago market, median prices of home sales in March posted a dramatic year-over-year spike after eight months of flat or declining prices.

Outside of the booming housing markets, these underwater mortgages are going to take a long time to clean up. In other words, that big drop in housing values with the economic crisis has long-lasting consequences.

I know this isn’t going to happen but I would love to see numbers on whether it might be possible that the new housing industry could receive a jumpstart through a mass mortgage reduction plan. If enough people could get out from under the underwater mortgages and sell their own homes and move (maybe this would be a requirement for getting a mortgage reduction), could this be a net economic gain in the end?