Hancock, NY – In a secluded spot here lies a vacationer’s dream: a three-bedroom ranch-style house with 14 acres of woods roamed by deer and turkey, just minutes from prime trout fishing on the Delaware River. The asking price is $107,000.

But even at this “just reduced” bargain price, said Leonard Piorkowski, a local real estate agent, he can’t make a sale. “One hundred seven thousand for 14 acres and a house and two garages, and we can’t sell it?” Mr. Piorkowski lamented as he guided a visitor across the property recently.

Coveted for its pristine water, pastoral landscapes and relative proximity to New York City, the Catskills region has long been second-home territory for urbanites. But brokers say many listings are languishing — and not just because of the lag in the nation’s economic recovery. The prospect that New York State will open the region to hydraulic fracturing, a controversial gas drilling process known informally as fracking, has spooked potential buyers.

There is concern that the drilling will not only ruin the natural environment but also depress property values, would-be buyers and real estate agents say.

Until state officials decide where, when and how the drilling process will unfold, many prospective owners seem unwilling to take the leap. But public opposition to fracking has grown in the four years since New York regulators have been studying its potential environmental effect, and Gov. Andrew M. Cuomo is taking his time making a decision. Administration officials recently announced another delay to allow the state’s health department to review drilling-related public health risks.

Some buyers are also deliberating. “What if I got there, and they start signing gas leases all around you?” asked Lauren Carner, 62, a school psychologist from Putnam County who once lived in the area and longs to return when she retires. “Even if I held out, my neighbors could sign leases. As gorgeous as it was when I bought it, it could turn into an industrial site.

“The whole idea seems so awful,” added Dr. Carner, who once owned property near the Delaware County town of Treadwell and fears that drilling would ruin the area.

Properties with gas leases, like the 14 acres in Hancock listed at $107,000, are a tough sell, some real estate agents noted. Leaseholders generally get money upfront and royalty payments on any sales of gas extracted from their land. The owners could end up earning millions of dollars, but they are also inviting large-scale industrial activity.

Many leases in New York were signed for five-year periods for as little as $3 an acre and royalties of 12.5 percent. Leaseholders have since formed groups to negotiate better deals with gas companies or file lawsuits to get out of their leases. In New York, companies have extended leases without the owners’ consent by invoking force majeure, a legal term referring to an unforeseen event — in this case, New York’s repeated delays in allowing fracking.

The drilling would take place on the Marcellus Shale — a rich natural-gas field that runs through several states and spans more than two dozen counties in New York. The most productive area is believed to be in the counties above the Pennsylvania border.

But gas companies have leased land all over the Marcellus Shale, and until it is known where fracking would take place, would-be home buyers fret. Fracking involves injecting vast amounts of chemicals and water into underground shale formations to force out natural-gas deposits. Potential buyers worry that their dream of a serene retreat could turn into a nightmare of water wells contaminated by drilling chemicals, country roads choked by truck traffic and views blighted by noisy industrial activity.

The uncertainty has also upended the long- and short-term plans of sellers, and homeowners who had been contemplating renovations.

Patricia Wallace, whose family has owned a house on the East Branch of the Delaware River near Hancock for generations, said fracking was a major reason she and her brother delayed replacing the 1,800-square-foot house where they spend their summers. The siblings had hired an architect in 2007 to design a new $500,000 structure within the footprint of the 240-year-old house, she said. But then the economy worsened and the gas companies began leasing land around them, as well as across the state line into Pennsylvania, where fracking got under way in earnest in 2008.

“It was one of the things that made us think,” said Ms. Wallace, 56, a professor of psychology at an Oregon college. “What if we invest the money and then fracking is allowed and everything is contaminated?”

But the old house started falling down, she said, and the siblings have now decided to rebuild by next summer, whatever happens. If there is fracking and they want to sell, she said, “there are people who probably would buy the property anyway because the waterfront is so nice.”

Some buyers from downstate have settled on a property only to back out. Six months ago, Arthur Gillett, a resident of Greenpoint, Brooklyn, and the research director for a food sustainability business, found what he considered the ideal spot: a Cape Cod-style cottage with a garden on four wooded acres near Livingston Manor in Sullivan County. At $140,000, the price was right.

But Mr. Gillett, 32, let it go, deciding to search closer to parkland and reservoirs where state officials have promised that fracking will be banned, even if it is allowed elsewhere in New York.

Mr. Gillett said he did not believe that oversight by state regulators would guarantee safe drilling, and he worries about the accidental contamination of water supplies. “If you’re really looking for something for use for a long time,” he said, “the idea of the groundwater being bad is just disconcerting.”

The New York State Association of Realtors says that residential sales across the state were up 6.7 percent in the second quarter. But in Sullivan County, a second-home destination that sits on the Marcellus Shale, sales were down 4 percent.

House hunters notice fairly quickly that the specter of fracking is as much a part of the landscape as ponds and lakes. Signs with a circle and backslash superimposed on the word “frack” are ubiquitous on lawns and porches in some towns, while placards in others proclaim, “I’m a friend of Marcellus.”

Some agents say they are bombarded with questions from would-be buyers: How likely is fracking in this area? How does one find out if leases are being signed in a given area?

“I’m not going to hide how I feel about this issue,” said Darren Wiseman, an agent in the Catskills area who opposes the drilling. He advises clients to do their own research. “I tell people, ‘Go online and type fracking and read about it.’ ” Landowners who welcome the economic boost from fracking dispute the notion that it deters buyers.

Noel van Swol, the president of the Sullivan-Delaware Property Owners Association, said that large parcels had become more desirable because of their broader drilling potential. His group represents owners of 70,000 acres in Sullivan and Delaware Counties who are ready to sign gas leases once the state approves fracking. “A lot of land has been taken out of the market over the last three years because people realize they’re sitting on a fortune,” he said.

Even so, plenty of agents worry that their livelihoods could be doomed, citing anecdotal evidence from colleagues in Pennsylvania. Jennifer Canfield, a former agent on the other side of the Delaware River in Wayne County, Pa., said she closed her office in 2010 after her business collapsed. “The last year, I sold two properties,” she said.

Although the drilling has so far been concentrated more than 60 miles north, she said, plenty of gas leases have been negotiated in Wayne County. That’s why she has had no luck selling a ranch house she owns on six acres near leased properties, she said. Originally listed at $219,000 two years ago, it is now going for $164,000. “Nobody looks at it,” she said, “because people don’t want to be anywhere near the drilling. If the economy turned around, we still wouldn’t get these people back.”

Still, some prospective buyers in New York State hold out hope. Mr. Gillett, who grew up near Fallsburg in Sullivan County and whose parents still live there, is anxiously awaiting a magic bullet: an unequivocal state decision that would rule out fracking in the area. “I love the mountain streams and the largely untouched forests,” he said, adding wistfully, “I have my deposit ready.”