At first, Punita Bhatt turned up her nose when her real estate agent suggested she consider a lakefront town house in Laurel. But after taking a look she was sold on it.

Roberta Oller and her husband William paid an additional $2,000 for a wooded, one-half acre lot and more privacy at Westridge in Prince William County rather than buy a similar home in Fairfax County.

Bhatt and Oller are part of the changing look of Prince George's and Prince William counties, two regions that for a long time were considered the ugly sisters of the Washington area. Now they are becoming more attractive bedroom communities.

The growth of commercial development in these counties has spurred local and national home builders to take advantage of the lower land costs and the demand for larger, more luxurious housing throughout Washington. Homes being constructed in these counties are selling for between $170,000 and $300,000 -- prices rarely spoken of 10 years ago.

While luxury homes in Fairfax and Montgomery may sell in the $300,000 to $1 million range, similar houses in Prince William and Prince George's are selling for $30,000 to $40,000 less in some cases, several builders said. In Prince William, the primary luxury home communities include Westridge and Montclair, both near Woodbridge, and the proposed Robert Trent Jones residential, commercial and resort development in Gainesville. In Prince George's, the areas include Tantallon, near Fort Washington; Laurel Lakes in Laurel; and Lake Arbor near the Capital Centre.

"I was a bit skeptical when we first went in there," said John V. Neill Jr., president of Fairfield Homes, which is building 150 houses in Westridge. "But frankly, it surprised me. We have found it to be a very fine market."

The increasing population and incomes in Prince William and Prince George's counties is fueling the demand for move-up homes. In Prince William, the median family income in 1985 was $38,946, ranked third behind Montgomery County ($41,385) and Fairfax County ($45,976), according to the Metropolitan Washington Council of Governments. In Prince George's County, the income was $33,332, higher than the $27,825 for the District, the council study said.

Many of the luxury-home buyers have already owned houses in these counties and are discovering that as they look for bigger and better ones, they are more frequently finding what they want in their own counties rather than in Fairfax or Montgomery counties.

"We looked in western Fairfax," said Dan W. Sclater, who lives in a four-bedroom colonial home built by Fairfield in Westridge. "But there were very small lots and you were out in the middle of a field. There were no trees."

Bhatt, of Laurel Lakes, who is an English professor at the University of the District of Columbia at Van Ness, said: "Friends told me, 'Laurel, you don't want to go there.' ... But when I saw the town house, I fell in love with it immediately. Now, when friends come by they can't believe it because of the spaciousness of the town house and that it's in Laurel."

Jeffrey Wilhide, a new homes consultant with Michael T. Rose Associates Inc., which is building one of the town house projects in Laurel Lakes, said the company is trying to reach people who don't like the maintenance required of a single family house, but who want the space.

The 2,500-square-foot, lakefront town houses start at $180,000, significantly higher than many traditional town housess being sold in the area for between $80,000 and $90,000. High ceilings, skylights, balconies and sunken living rooms are among the amenities in the Laurel Lakes project.

Winchester Homes is building luxury brick-front town houses in the same development with up to 2,000 square feet of living space. It also plans to build single-family homes costing between $275,000 and $400,000 on land bordering the Prince George's Country Club.

"This is not 'P.G. County,' " Wilhide said. "It's Prince George's County. People think of Landover when they hear 'P.G. County.' The {Laurel Lakes} area has low crime, it's centralized and close to the Baltimore-Washington Parkway."

Israel Krause, president of Krause Design and Construction Inc., and his brother Michael, vice president of the company, are designing and building Riverview, a project of 15 custom homes in the Fort Washington area of Prince George's County. Some of the lots overlook the Potomac River, and all are near woods and on cul-de-sacs.

"We've taken an area here that many people thought of as a ... dirt-road section of Maryland and brought some dignity to it," Israel Krause said. "It seems so far away from the hustle and bustle, but it's close to the Beltway, the Indian Highway, schools, shopping, golf and the marina."

Builders in Prince William said they are trying to create a quiet, serene housing environment that is still close to some of the conveniences of living downtown.

"It's a little city unto itself," said Fairfield's Neill about Westridge. "There's Tackett's Mill {a nearby shopping center} and lots of new office development. There are a lot of professionals in the area and the whole complexion of the county is changing."

Anthony J. Sala, senior vice president of the Ridge Development Corp., developer of the 475-acre planned residential community in Prince William County, said his company talked to real estate agents, builders and residents of its Lake Ridge community before moving ahead with the Westridge project two years ago.

As a result of those meetings, Sala said the company designed a luxury home community that had plenty of trees, a variety of builders, the availability of custom lots and shopping and recreational facilities to cater to the wealthier new residents.

"Ten years ago, this whole concept would never have been thought of," Sala said. "It's a jurisdiction that is getting more and more populated with private companies and with middle- and upper-income residents."

Parris Glendening, Prince George's County executive, said the growth in the number of high-technology companies moving to the county has helped boost the number of people making more money and looking for better housing.

"For many purchases, moving up to the next level of housing in Prince George's was difficult," he said. "In the past, there wasn't quite a range. If you wanted to move up from a $140,000 house, there was nothing in the lower $200,000" range.

Other factors contributing to the demand for luxury housing in the area include improvements in the county's roads, schools and efforts to zone land that's ready for development, Glendening said. "As more people move into the county, they see it's a nice place to live as well as to work."

Gary Lachman, senior vice president and chief operating officer of the mid-Atlantic region of Community Holdings Corp., the developers of Lake Arbor, said Prince George's County definitely has a market for $250,000 and $300,000 homes. But builders must expect expensive houses to stay on the market longer than the less expensive houses because the number of buyers is smaller. At the same time, he said, buyers will most likely get more for their money in Prince George's or Prince William than in Potomac or McLean.

"What qualifies for a luxury home in Prince George's County costs so much less than many of the homes in Fairfax and Montgomery counties," Lachman said. "For $180,000, at least in Lake Arbor, you can get a four-bedroom, two-bath home on the fairways of a golf course with all the amenities. In terms of value, that's a lot to offer.