Fairfax County supervisors turned aside a strong and controversial lobbying effort by real estate and building interests yesterday and unanimously approved 9 to 0 an ordinance aimed at protecting purchasers of new houses in the rapidly growing suburb.

Supervisor Marie B. Travesky (R-Springfield), who had attacked the opponents of her measure for what she called a misleading campaign, said yesterday she was happy and surprised by the vote.

Under the measure, sellers of new homes in the county will be required to provide prospective buyers with certain information about utilities, insulation, restrictive covenants, taxes, and sewerage. The law is effective June 1 and will directly affect Fairfax's largest industry, homebuilding.

Only a handful of real estate agents and builders showed up for yesterday's board meeting and none, to Travesky's surprise, even bothered to attempt to speak against the proposal, which will apply to the sales of newly constructed homes.

"I'm disappointed," said Herbert L. Aman III, president of the Northern Virginia Builders Association, which mounted the vigorous campaign against the measure along with the Northern Virginia Board of Realtors.

A man blamed the board's surprise vote on press coverage of the campaign against Travesky's proposal. "It turned into a good-guys-versus-badguys thing," he said, adding the opponents ended up portrayed as the "bad guys."

Joseph Hayden, a spokesman for the Realtors, joined in expressing disappointment at the board's action, but said he was pleased that the approved ordinance will apply only to sales of new homes.

The campaign against the proposal culminated last week with controversial newspaper advertisements that erroneously claimed that home sellers could be sentenced to jail under the proposal. The claim and the extent of the campaign angered most supervisors, who accused the industry groups of using deceptive advertising and scare tactics.

"So much has been said about the proposal that is erroneous that it has taken a lot of board work to get it straight," Travesky said before the vote.

Supervisor John P. Shacochis (R-Dranesville) who said he originally believed he county did not need the bill, said he had changed his view. "The last couple of weeks have convinced me that we do. I'm sorry we are not extending it to all homes."

Shacochis accused the real estate industry of failing to police itself. "It's unfortunate that the few bad apples spoil the barrel," he said.

The unanimous decision surprised several supervisors, who said they had expected Board Chairman John F. Herrity to vote against the ordinance. Herrity, who reportedly called several supervisors during the weekend to expres his opposition, said yesterday that he supported the bill because it was limited to new homes "where most of the problems lie."

County officials praised the ordinance yesterday and said it could help ease the rising volume of complaints the county is receiving about new home sales.

"To my knowledge, this is a unique consumer protection aid in the Washington metropolitan area," said Ronald B. Mallard, head of the county's Consumer Protection Department. "There is nothing like it in Virginia, certainly."

The ordinance calls for a form to be given to prospective buyers by sales agents. It will include a list of questions, many of them to be answered by a yes or a no, concerning restrictive covenants, homeowners' association fees, the names of utilities serving the property and whether it is served by public water and sewer lines.

The form also includes a list of telephone numbers from which buyers can seek more information and advice ranging from how to choose title insurance to whether to have an independent engineer inspect the quality of workmanship in the house.

The ordinance will expire in three years unless revived by the board, under a so-called "sunset" provision requiring review of the law. County officials will report to the board quarterly on the effects of the ordinance, which carries a maximum penalty of a $500 fine.