CINCINNATI—Here in Hamilton County, where one in seven people lives beneath the poverty line and budget cuts have left gaps in the schools and sheriffs department, residents are bracing for more belt-tightening: rollback of a property-tax break promised as part of a 1996 plan to entice voters to pay for two new stadiums.

The tax hit is just the latest in a string of unforeseen consequences from what has turned into one of the worst professional sports deals ever struck by a local government—soaking up unprecedented tax dollars and county resources while returning little economic benefit.

With a combined estimated cost of $540 million, the stadiums—one for football's Bengals, the other for baseball's Reds—were touted by the teams and county officials as a way to generate cash and jobs. The Bengals, who had threatened to relocate if they didn't secure a new home, drove negotiations. And it is that deal—the more lucrative arrangement struck with the teams—that has fanned the county's current struggles.

An analysis by The Wall Street Journal shows that of the 23 National Football League stadiums built or renovated between 1992 and 2010, only two involved a single county government willing to shoulder the debt burden necessary to build costly new facilities. Of those 23 deals, the Bengals pact was unusually lopsided in favor of the team and risky for taxpayers—the result of strained negotiations between a local government and the professional sports team it was anxious to keep.

At its completion in 2000, Paul Brown Stadium had soared over its $280 million budget—and the fiscal finger-pointing had already begun.