Fairfax County officials agreed yesterday to allow one of the largest land developers of the western end of the county to move ahead with housing construction plans that exceed the county's new growth limits near the Occoquan Reservoir water supply.

With both county officials and landowners claiming victory, the two sides agreed to an extensive settlement in the first of 30 lawsuits challenging the county's right to control growth in the western quarter of the county. The area serves as the watershed for the county's drinking supply.

"This is a victory for property owners," said Francis A. McDermott, who filed several of the suits, including the one settled by the county and Fairfax Station Associates yesterday. The development firm is partly owned by attorney John T. (Til) Hazel, one of the county's most prominent developers.

But county officials also are claiming victory in the settlement, even though it allows Fairfax Station to begin developing its remaining 300 acres of land in the watershed.

The developers, in the settlement, reversed their stand contending that the county's growth limits, imposed last summer, are unconstitutional and violate property rights. County officials say they hope to use the developers' concession that the new ordinance is legal to fight the remaining 29 suits challenging the county's laws on the same grounds.

But attorneys representing the landowners argue that because the suit ended in a settlement rather than a court decision, Fairfax Station's concessions won't necessarily be used against developers involved in the other suits.

"They [the county] gave away their lawsuit," said Marc E. Bettius, who is representing other land developers in suits against the county. "They've given away 300 acres in the middle of the watershed and what they got was a lot of empty concessions."