More than 53,000 Orange County homes that had more debt than they were worth have regained equity this year so far, according to Irvine-based real estate data firm CoreLogic.

As of the third quarter of 2013, 29,514 Orange County homes were "under water," meaning that their owners owed more on the mortgage than the homes were worth.

That represents 5.4 percent of all Orange County homes with a mortgage. By comparison, 82,586 O.C. homes, or 15 percent of mortgaged properties, were under water at the end of 2012.

At least 100,000 under water homes regained equity since the third quarter of 2009, when O.C. had 130,364 underwater homes.

That's a 77 percent decrease in under water homes. The decline in under water homes accelerated in the past year in conjunction with rising home prices. More than 67,500 homes regained equity in the year ending in September.

Nationwide, 6.4 million homes were under water in the third quarter, or 13 percent of all homes with a mortgage, CoreLogic reported. By comparison, more than 11 million homes – or almost a fourth of mortgaged U.S. residences – were under water at the end of 2009.

CoreLogic reported that more than 3 million U.S. homeowners regained equity this year alone. "Rising home prices continued to help homeowners regain their lost equity in the third quarter of 2013," said CoreLogic Chief Economist Mark Fleming.

The latest report showed also:

•California had 894,560 under water homes in the third quarter, or 13 percent of mortgaged homes.

•Nevada was the state with the highest percentage of mortgaged properties under water: 32.2 percent. •Orlando had the highest percentage of under water homes among the 25 largest U.S. metro areas: 32.3 percent.