PHILADELPHIA — When Mehmet Oz bought a bucolic farmhouse in Montgomery County last year, he not only acquired property in the state where he’s running for Senate, but also he scored a $50,000-a-year tax break.

While the purchase seemed designed to put to rest questions about Mr. Oz’s ties to the Keystone State that continue to dog his campaign, the large tax rebate could provide ammunition for Democrats seeking to paint Mr. Oz as a wealthy, out-of-touch carpetbagger from New Jersey. And while owning property may signal the celebrity doctor’s commitment to Pennsylvania, he’s still not living in the home — and it’s unclear when he will be.

The cardiothoracic surgeon and former daytime TV personality’s use of the tax incentive is totally legal and was in place decades before Mr. Oz purchased the property, according to local officials and public records. “I inherited it,” Mr. Oz said in an interview last week. “And I intend to preserve that land and not do anything that would hurt it.”

A $50,000 tax break

The tax incentive is part of a controversial state program designed to encourage the preservation of farm or forestland that overwhelmingly benefits wealthy landowners like Mr. Oz.

And while Mr. Oz says he’s simply awaiting renovations before he moves into his new home, there’s little sign of work at the property, and he continues to live at his in-laws’ home in the nearby borough of Bryn Athyn, Montgomery County.