The Virginia courts have delivered another setback to home rule in the Washington suburbs, striking down a Fairfax County ordinance that required builders to make certain property disclosures to prospective new home buyers.

Invoking a common law doctrine known as the Dillon rule, Fairfax Circuit Judge Lewis Hall Griffith said, in an opinion issued Sept. 9, that the disclosure ordinance is inconsistent with state law and an invalid use of powers granted by the state to the county's Board of Supervisors.

It was the second time in two weeks that the Dillon rule -- which holds that all powers not specifically granted to counties belong to the state -- has been used to quash consumer legislation passed by the county's governing body. On Aug. 28 the Virginia Supreme Court annulled controversial local laws passed by Fairfax and Loudoun county supervisors that were aimed at reducing litter in the county by requiring deposits on beverage containers.

The home buyers' ordinance, in effect since June 1979, was passed over the strong objections of Fairfax's powerful real estate and home building interests. Two builders later went to court seeking to have the measure thrown out.

The ordinance required sellers to provide information about restrictive covenants, utilities, insulation, schools, sewerage and other basic items. The maximum penalty for failing to make the disclosures was $500.

Springfield District Supervisor Marie B. Travesky, who sponsored the home buyers' ordinance, said yesterday that the board would now have to decide whether to appeal the ruling or seek the General Assembly's approval of similar legislation.

"I would not be optimistic of anything like that getting through the assembly," Travesky said. "The lobbying against it in Richmond would be very intense."

Travesky said the board had considered the Dillon rule as a possible obstacle to enactment of the ordinance, "but I frankly felt it was worth the gamble . . .I was sorry to see they took it to court."

Compliance with the ordinance was "very good," reported Travesky, who said she was heartened to receive assurances from the Northern Virginia Builders Association that it would urge continued compliance on a voluntary basis.

The judge's ruling, she added, came as no surprise after the Virginia Supreme Court decision on the bottle bill.

Judge Griffith said the disclosure ordinance was not necessary to protect the public welfare. While he conceded it did not conflict with Virginia statutes, he said the measure did conflict with a legal tradition which places a responsibility on purchasers to examine before buying.