Fairfax County officials and area developers are on a collision course over proposed get-tough soil regulations that builders claim could needlessly strap them with hundreds of thousands of dollars in survey costs.

Touching off the controversy is a concern by the county Office of Environmental Management that Fairfax homeowners -- and ultimately the county government -- will be hit by large bills generated by the costs to repair buildings sitting atop marine clay and other shifting surfaces.

The county has had a history of ground water-related problems, especially in the Lee and Centreville districts, with collapsing basements, cracking steps and serious flooding triggered by improper development, according to county officials.

With increasing frequency, according to Fairfax's chief environmental official, residents are looking to the county to pick up the costs of their home repairs.

The rising tide of complaints has spurred the county to turn its attention to those persons it considers to be the source of the problem: the builders.

The result is new regulations, drafted by the environmental management office and expected to be presented soon to the Board of Supervisors, that would require developers to locate the source of ground water problems as a condition for obtaining rezoning.

Currently, developers can delay the complex soil surveys until late in the zoning process, long after approvals have been granted and at a time when public attention on a proposed development has waned. That is "too late in the game to get that kind of information," said Claude G. Cooper, county director of environmental management.

"If this kind of policy was in effect, some homeowners would have saved thousands of dollars" in repair costs, added Supervisor Joseph Alexander (R-Lee).

Developers "ought to do that before they do anything," planning commission member John H. Thillmann said of those contemplating building in Fairfax. Thillmann, who represents the Centreville district, said he has little time for complaints by builders that the requirement would pose an unfair expense.

"Maybe they ought to undertake the soil study before they buy the land," Thillmann said, alluding to the builders. "If you're smart, you'll want to find out whether the land is capable" of withstanding the planned construction.

The local building industry is adamantly opposed to the proposed county policy, which was denounced as ill-conceived and "unreasonable" by Samuel A. Finz, chief executive officer of the Northern Virginia Builders Association.

"There's not a single developer who's not going to spend the money he needs to spend to make the land stable, but it's unreasonable to expect a developer to undertake an expensive study in advance of a rezoning," Finz said.

He said such a policy would require a builder to "put up a lot of money up front without any assurances that he will be able to get the density he wants." Finz said that such a study on a large project could cost a developer $50,000 to $100,000.

Cooper said he and his staff will review the concerns of developers before proposing the revised policy to the Board of Supervisors. He said, however, that the time has come to shift the responsibility for faulty location, as well as for poor construction, to developers.

"It's only fair that buildings be located on the best possible ground," Cooper said, adding that the only way to determine that is to have a soil study in hand before county officials vote on a rezoning.

Cooper noted that soil problems often surface several years after a building goes up and that by then it is too late to make the builder accountable. He said more homeowners are trying to recover damages from the county government for repair costs, a trend that that could turn into a major financial drain on the county.