Fairfax County officials have told developers in the fast-growing Fair Oaks area that a new sewer system there will accommodate less development than they originally projected -- casting a cloud over the county's proposed government complex and private development at Rte. 50 and Interstate 66.

County officials insist there is adequate sewage capacity to build the proposed $70 million government center, but charge that some private developers have taken more sewage capacity than they need, leaving the area with no excess capacity.

The developers say the county warned last spring that it would prohibit several property owners with sewer rights from developing parts of 1,460 acres near Fair Oaks. The proposal has left developers angry about making concessions.

"I am not aware of any developers involved . . . who would be willing to give up any of their capacity," said Jack W. Carney, a developer who owns 80 acres in the disputed area. "There's nobody who's going to be willing to give up those" rights.

Richard J. Gozikowski, director of the county office of waste management, said the county's request was not unreasonable. He said several property owners "may be holding onto sewer taps that may well be in excess of what they will use" and that the county was asking them to "redistribute the sewer rights to more accurately reflect the potential uses in the area."

"There has to be a compromise," Gozikowski added. "If there isn't, it could put a stumbling block in the way of everything out there" in the Fair Oaks area.

The two sides have been meeting privately for several weeks to resolve the impasse, which centers on the county's decision last spring to tell those building or planning to build on the land in the area that they will have to restrict their construction plans.

Triggering the controversy was the county office of waste management's recent letter to the "50-66 Association," a group representing developers and property owners in the area, informing them that peak sewer capacity had been reached in the area and directing them to seek ways to alleviate the problem.

The county's letter, in effect, warned property owners in what is known as the 50-66 development corridor that they would be prohibited from building to densities to match the amount of sewer capacity they have bought over several years.

Developers and property owners are balking at the county's request, claiming the right to maintain control over sewer rights they purchased. They also argue that the county appears to be overlooking the fact that the private developers involved in the dispute financed the bulk of the new sewer line -- worth more than $3 million.

Fairfax County Supervisor Audrey Moore (D-Annandale) said the problems that have surfaced concerning the 50-66 corridor reflect "a classic example of the county's lack of planning.

Many county officials, she said, "are in love with development and have a boomtown philosophy -- build first and we'll worry about playing catch-up on roads and sewers later on."

The 50-66 Association, which is composed of 35 developers with the intention of building in the Fair Oaks Mall area, joined forces in 1964 to seek the construction of a new sewer line that would be needed to handle any significant development there.

After years of uncertainty and delays, the association entered into a joint agreement with the county in 1971 under which the association put up $3.3 million to build the sewer line. The county assumed the line's maintenance costs. The association reserved the authority to assign rights to the new sewer to various property owners.

The county purchased the sewer rights for the 183-acre tract slated for the construction of the proposed government center.

Gozikowski was dubious about his plan's chance for success, saying of the property owners, "I don't expect that they'll just willingly give their sewer capacities up. It will probably have to be negotiated."

Carney, chairman of the 50-66 Association, said members of his group are working with the county staff to resolve the problem.

"This is no war," he said. " We are trying to resolve a problem."

But Carney was pessimistic about the chances for a speedy settlement.

"The association and its members view the reservation of sewer capacity as a personal right. It came with participating in the cost of the system."

Moore said those developers who are now complaining also must shoulder a large share of the blame for the problem. She said they "designed a sewer system to take care of a certain amount of sewage and they knew what that amount was when they lobbied for higher density development." She said that they, like the county, "did not pay attention to things like road and sewer capacity."

The proposed government center, which calls for moving some county offices out of Fairfax City, has been highly controversial. The county board has been debating the idea for several years and most recently withdrew from the November elections a proposed bond issue that would have called for initial funding for the project.

Its proponents say the proposal remains alive and ultimately will be approved by county officials.