Already, the Schwartzes' proposal has been scaled down from two homes to one; the designs have been redrawn at least a dozen times; and the storm-water management plan has reached such a level of complexity and expense that James M. Scalise II, the engineer who devised it, calls it ''the kind of thing I would normally design for a Wal-Mart, not a private home.''

And the project is still awaiting approval by the Conservation Commission; a yes vote is expected at a hearing to be held on Tuesday night.

The cause of all the controversy is a little-known environmental regulation called the Berkshire Scenic Mountain Act, a bill passed by the Massachusetts State Legislature and adopted by the town of Richmond in 1974 to protect its watershed resources and preserve the scenic qualities of the mountainous area. Towns are not required to comply with the act, and only 4 of the 31 towns in the Berkshires have adopted it.

In Richmond, landowners who hope to build in a protected mountainous zone must meet a number of guidelines: Their projects must not be visible above the ridge line, tree-cutting must be limited to one-quarter of an acre and it cannot cause erosion or flooding that would damage water quality.

Town officials said that the proposal by the Schwartzes failed on all three counts. The couple countered that the Conservation Commission has been overzealous in its enforcement.

Richmond is only one of a number of towns across the country with a large population of second-home owners where these kinds of conflicts are playing out. As land grows scarce in popular weekend communities, the forces of development are increasingly coming up against preservationists trying to protect the verdant hillsides, pristine streams and woodland vistas that drew vacationers in the first place. Although there is no tally of similar zoning restrictions nationwide, ordinances that restrict hillside building are fairly common, particularly in western ski towns like Sun Valley, Idaho; Park City, Utah; and Jackson Hole, Wyo.

But unlike the Berkshire Scenic Mountain Act, the regulations typically found in the West do not link mountaintop protection to wetlands conservation, a fact that makes those rules easier to interpret and thus to enforce.

In Salt Lake City, for example, open space legislation put into effect in 1994 to limit urban sprawl restricts building in the foothills of the Wasatch Mountains, citing the need to protect the visual qualities of the mountains themselves. The scenic views are considered an economic asset and a tourist attraction, said Deeda Seed, communications director for Mayor Rocky Anderson.

As second-home ownership continues to grow -- statistics released last week by the National Association of Realtors said 13 percent of all houses sold in 2004 were vacation homes, for a total of 1.02 million properties -- tensions are only likely to rise.

''The countryside is rife with conflicts over the use of land now that agricultural land is less productive,'' said Alexander von Hoffman, a senior fellow at Harvard University's Joint Center for Housing Studies in Cambridge, Mass. ''The other force is that with the affluence created over the last 20 years, Americans are willing and able to indulge their love of rural scenery.''

Indeed, according to a study of second-home ownership by Professor von Hoffman's colleagues at Harvard, second homes account for about 5 percent of all residences in the United States. Their density in the Northeast is much higher. As of 1990, one-fifth of all second homes in the United States were concentrated in only 20 counties, most of which were in Florida or near the Boston, Los Angeles, New York, Philadelphia or Phoenix metropolitan areas. Half of all second homes in the country were found in a mere 150 counties in those areas. Such a high concentration in such a small number of towns sets the stage for particularly ugly showdowns, like the one in Richmond, where nearly one-quarter of all homes are seasonal.

Although this is the first challenge to the Scenic Mountain Act in the Berkshires, these tensions are common all over the region as popular second-home communities strive to balance environmental and aesthetic concerns with the desire of new homeowners to build ever grander private residences. In Monterey, Mass., one letter writer complained to the local paper of trophy houses that ''hang from the hills like so many Dracula's castles.'' A bit farther south, in Lakeville, Conn., plans to build a large lakeside home on the site of a much smaller structure led to cries of ''Hamptonization'' on the part of town residents, although the house was eventually built.

In Richmond, the dispute has matched neighbor against neighbor; town meetings have been reduced to shouting matches; and the Scenic Mountain Act itself has become a political lightning rod.

It has also served to reveal the fault line that has long run invisibly between the town's full- and part-time residents. Mr. Schwartz says that the seven-member commission is biased against second-home owners. ''It's a clear case of nimby-ism,'' he said. ''They have a stake, and they don't want anyone else to have one.''

For her part, Holly Stover, the chairwoman of the Conservation Commission, has suggested that native Richmond residents are better stewards of the land than newcomers. ''The owners are part-time, with not the same interest as the town,'' she said, speaking of the Schwartzes. ''Their neighbors are full-timers who were brought up in Richmond. Their grandparents and grandparents' grandparents lived here all their lives.''

The Schwartzes and Kurt Hoelter, their builder, first applied to the commission for a building permit in July 2003. Their initial plan was to build two houses with a shared driveway set into a plateau on the hillside. This plan was immediately unpopular with the Schwartzes' neighbors, because of the placement of the driveway. For that reason, in 2004, the project site was moved closer to Osceola Road and reduced to a single house on 2.5 acres, with the other plot to be donated to a local land-conservation group for tax purposes, a solution that muted most of the community opposition.

BUT the Conservation Commission still refused to grant a building permit, citing concerns about drainage and flooding from storm water runoff that might damage wells and springs below the site. The committee also suspected that the plan would require more clear-cutting on the site than Mr. Hoelter originally contended and that the blasting might disturb the water table, which is unusually shallow in that area of Richmond.

''We didn't think the heavy machinery could even come down the hill safely to dig the trench,'' Ms. Stover said. At the next meeting, the Hoelter-Scalise team proposed new plans: one to deal with runoff during construction, another to address landscaping issues previously raised by the committee in earlier meetings. But they were still refused.

After nearly a year of fruitless negotiation with the town, Mr. Hoelter appealed to the state, the first time a challenge has been filed since the Scenic Mountain Act took effect. The case went to the Massachusetts Department of Conservation and Recreation, which last fall ordered another round of talks between the sides. The commission's most recent conditions, sent to Mr. Hoelter in January after a tense public hearing in December, place 15 restrictions on the project, including the length of time that soil can be exposed at the construction site, the height and placement of outdoor lighting, and even the color paint that must be used on the finished house in perpetuity (earthy tones of brown, gray or green are specified). It also lays out 60 general conditions for mountainside developments. Ms. Stover said that the guidelines would prevent erosion and make the finished house less visible.

And even though Mr. Hoelter and the Schwartzes are expected to accept the restrictions at the coming meeting, Mr. Hoelter worried that some of the provisions exceeded the purview of the Scenic Mountain Act. ''It becomes a land-taking issue,'' he said, noting that the Schwartzes have paid taxes on their property as a buildable lot for the last 30 years.

The case has highlighted several unforeseen consequences of this kind of environmental law. In Monterey, Mass., where the legislation was adopted two years ago, clear-cutting accelerated in the months before the law took effect, as developers raced to prepare lots while they still could. And as buildable land becomes scarcer in areas protected by this kind of law, the cost of housing rises substantially, forcing many local families out of the housing market entirely.

Indeed, across the country, opposition to environmental regulations like the Scenic Mountain Act is growing. The Colorado Northern Front Range Mountain Backdrop Protection Study Act, a bill introduced by Rep. Mark Udall, Democrat of Colorado, that would have prohibited development in the Front Range of the Rocky Mountains, failed to pass in the 108th Congress. In November in Oregon, a state that has some of the strictest environmental protection in the nation, voters passed Ballot Measure 37, which provides compensation or exemptions to property owners whose investments have been hurt by restrictive zoning.

Even though Richmond is already one of the most expensive towns in the Berkshires, Mr. Hoelter says that the opposition to his project may backfire on Osceola Road. With all the costs associated with getting the project approved, the house that will eventually be built there is more likely to look like ''cheeseburger than filet mignon,'' he said.

And Ms. Stover agreed that a house at that site would be much less visible to neighbors if it were set back on a plateau, as in Mr. Hoelter's quickly rejected original plan.

But whatever the final aesthetics of the place, along with the Scenic Mountain Act, it's something the neighbors will have to live with for a very long time.

Published: 03 - 11 - 2005 , Late Edition - Final , Section F , Column 3 , Page 1