Although numerous complaints from home buyers in Fairfax County spurred the Board of Supervisors there to enact an information disclosure law this week, county consumer protection officials say they don't anticipate an increase in communications from purchasers when the law goes into effect June 1.

The law requires new home sellers to disclose to the purchaser before any agreement is signed information describing the location of the property and the assessed value of land and improvements.

The names and telephone numbers of utility companies serving the house, type and amount of insulation used in construction, availablilty of public water and sewer and identification of neighborhood facilities such as schools, fire and police stations and hospitals must also be disclosed.

In addition, the sellers must furnish purchasers with a bill of particulars describing what rights the buyer has, county code requirements for inspections and other educational information. The law does not apply to resale houses.

Homebuilding is Fairfax's largest industry and complaints about house defects have been on the increase there -- and in other jurisdictions -- in recent years. The supervisors said they had passed the legislation because the industry had failed to police itself.

Ronald B. Mallard, head of the county's consumer protection agency, said that while he expects to continue to receive complaints about house structural problems, they are usually code violations are are not covered under the new information disclosure law.

If a lesller does violate the new law by not disclosing the right information, the purchaser can complain to the consumer affairs office, which will investigate the complaint and then refer it if necessary to the Commonwealth's Attorney's office for prosecution. Violators are subject to a $500 fine, Mallard said.,

The disclosure form is given directly to the purchaser and does not have to be filed with any county government agency, Mallard said.

The supervisors' unexpectly quick action on the law stunned some Northern Virginia builders.

A spokesman for the Northern Virginia Home Builders Association said builders had asked the board to wait for a ruling on the legality of the law from the Virginia attorney general's office before acting.

The unanimously approved law, which builders and realtors opposed, was enacted in "an atmosphere that signals this is an election year for those supervisors planning to seek reelection," the builder spokesman said.

While the supervisors maintained that the law would help ease the increasing number of complaints the county receives about new houses, builders contend that they can solve any problems themselves.

The builders' spokesman said the ordinance was an "overkill" designed to reduce complaints to supervisors.

The adopted form will include, for instance, a telephone number for advice on whether to have an independent engineer inspect the quality of workmanship in the house for a fee.

One large-volume building firm reported that it had responded to 24,000 warranty items in recent years.