A Fairfax County judge approved an agreement yesterday between county officials and developers that upholds an earlier court decision sharply restricting development in the Occoquan River Basin. The pact virtually eliminates further appeals of county-imposed zoning limits in the Occoquan case.

The protracted case, which has spanned four years and pitted county officials against the area's powerful developers, ended when Circuit Court Judge Johanna L. Fitzpatrick signed an order late yesterday sustaining the county's right to limit development to no more than one house on each five acres of land in the rural southwestern portion of the county. Developers originally fought to build one house on each acre.

Richard W. Hausler, an attorney with the firm of Hazel, Beckhorn and Hanes, which represented 25 of about 40 landowners who challenged the county's zoning laws, yesterday confirmed that the order had been signed.

Fitzpatrick could not be reached late yesterday and county officials would not comment on the order.

The order, a key setback for developers, upheld the constitutionality of the county's zoning regulations and dismissed the builders' claims that the county's attempts to restrict building in the area are discriminatory.

It also dismissed other suits filed in Fairfax Circuit Court contesting the original Occoquan decision by Fitzpatrick in January and threw out all claims for damages. Separately yesterday, U.S. District Court Judge Albert V. Bryan Jr. in Alexandria dismissed the two federal court cases in which developers were seeking $275 million in damages because of the county's action.

The county's stringent zoning regulations, which have been tied up in the courts since they were adopted in 1982, reduced the zoning on 40,000 acres in the Occoquan and imposed tough water control standards for new construction in the area.

Under the order signed by Fitzpatrick yesterday, development already under way on 1,450 acres -- or about 4 percent of the area in question -- will be allowed to proceed under the previous zoning regulations. However, the builders still must obtain all their approvals within 18 months and comply with updated water-control standards.

Fairfax Supervisor Audrey Moore (D-Annandale), the leading proponent of limiting development in the county, hailed the agreement as "a major victory" in that battle. The litigation, Moore said, "was a major fight between the developers and the people -- and the people won. And that's a first."

But representatives of area developers continued to assail the county's zoning decisions as harmful to the interests of a rapidly developing county.

Marc E. Bettius, an attorney for several developers in the case, said the court rulings "deprive builders of a legitimate opportunity" to develop the Occoquan Basin and will deprive the county of development that would bolster the county's commercial base.

"Fairfax is trying to build a tremendous industrial-commercial base, and we're running out of land," Bettius said. "History will have to be the judge of who's right."

Bettius said the settlement gives his clients a "monopoly" in the Occoquan. He described the results of the litigation as "a tremendous bonus to my clients."

He said, though, that the decision unfairly restricts the rights of builders not grandfathered in under the new regulations.

County officials have said they wanted the area of streams, forests and hilly meadows that drains into the Occoquan Reservoir to remain undeveloped to protect the drinking water supply for some 600,000 Northern Virginia residents.