Demand for new housing in the Washington region is outstripping supply and will continue to do so for 20 years, ratcheting up prices, spurring development farther into the geographical fringe and lengthening commutes, according to a study by George Mason University's Center for Regional Analysis.

The forecast comes as many local jurisdictions place more stringent restrictions on home development. On Monday, for example, Loudoun County supervisors approved zoning that bars standard suburban development from about two-thirds of the county and shrinks the number of potential new dwellings by about 60,000.

"The basic problem is that local governments are not planning for enough housing to support the economic growth they are expecting," said John McClain, a GMU researcher who did the study with GMU economist Stephen S. Fuller. "In terms of the region's economy, this could be the straw that breaks the camel's back."

The forecast was prepared for the region's building associations and was released at the university yesterday at a meeting of builders, developers and planners. It was based on employment and housing projections that counties file with the Metropolitan Washington Council of Governments.

During the 1990s, according to the report, the demand for new housing created by new jobs outpaced supply by about 43,000 units. By 2025, that gap is projected to be 218,000 homes.

Builders at yesterday's meeting said that so-called slow growth restrictions adopted locally in recent years have accelerated rather than curbed suburban sprawl, pushing development farther and farther from the region's job centers.

"I used to do business within one hour of the office," said Richard J. Thometz of Hailey Development in Burtonsville. "Now it's three hours. We are competing for land out in York, Pennsylvania; Sussex County, Delaware; and Berkeley County, West Virginia."

County leaders throughout the Washington region argue that restrictions on residential development are necessary to preserve open space and limit the cost of schools and other services required by residents. At the same time, local governments typically try to attract business development, which provides jobs and bolsters the tax base. In other words, they seek boardrooms, not bedrooms.

Accordingly, the study projects that through 2025, rapid job growth in Loudoun will outstrip residential growth -- 207,700 new jobs vs. 89,500 new homes -- resulting in a shortfall of about 40,000 homes, assuming an average of 1.6 workers per household.

"No one is disagreeing that there is a shortage of housing in the region," said Julie Pastor, planning director in Loudoun. "Hopefully, when we get our jobs, more people who live in Loudoun County will work in Loudoun County."

Loudoun Board of Supervisors Chairman Scott K. York (R-At Large) said leaders throughout the region must grapple with the problem, because new workers will have to live somewhere.

"The question is: What are we going to do with growth if no one is going to pay for it?" York said. "The fact of the matter is that the home-building industry does not want to cover the costs of new development. They gripe and they gripe and they gripe, but they do very little to help us cover the costs of the new schools. The taxpayers do."

Stewart Schwartz, executive director of the Coalition for Smarter Growth and an advocate of development restrictions, acknowledges that the housing supply has not kept up with job growth in some jurisdictions. "Fairfax in particular has captured an awful lot of jobs without providing an adequate amount of housing," he said. ". . . People are commuting long distances for jobs here."

But Schwartz dismissed criticism of development restrictions such as Loudoun's, arguing that residential development should be clustered around Metro stations and in other densely developed areas near job centers.

While builders attribute the region's soaring housing prices to local building restrictions, it is difficult to determine how much of the increase relates to an imbalance between supply and demand and how much relates to other factors, such as low interest rates.

Despite a sluggish economy, housing prices in the region jumped 11 percent in the 12 months that ended September 2002, according to the Office of Federal Housing Enterprise Oversight. But other large metropolitan areas such as Boston and New York experienced similar increases.

Many planners believe that the tight supply of new housing is pushing prices up.

"First of all, we do recognize that we have a severe housing issue," said Drew Dedrick, chief of the research center at the Montgomery County Department of Park and Planning. "But we do know that we are a mature county and that there is not a lot of vacant land."

What about Montgomery's 90,000-acre agriculture preserve, which has some of the region's strictest limits on housing development?

"I don't see any way that the rural wedge will be broken," Dedrick said.

Instead, Dedrick forecasts more houses elsewhere. "I think there will be tremendous pressures in the outer counties to develop," he said.