Fairfax County's latest attempt at belt tightening is pinching the powerful Northern Virginia Builders Association.

The county is attempting to make builders foot most of the $10-million-a-year costs of inspecting plans and reviewing construction of new homes in Fairfax, the major work of the Department of Environmental Management. Prince George's, Prince William and Arlington counties recently enacted similar increases.

In fiscal year 1982, Fairfax builders fees covered about 47 percent of the department's costs and a proposal to raise the fees to collect a total of $7.6 million, which would cover about 75 percent of its budget, is currently before the Board of Supervisors. It plans a hearing this month.

In a meeting yesterday with members of the builders association, Mason District Supervisor Thomas M. Davis III, a Republican, said the builders should have to pay their share. The costs "can either be paid by the retired widow with fixed income, who gets no benefits from it, or those who benefit from it," he said. "To put it bluntly: I think it should be paid for by those who are benefiting."

Builders questioned whether the board had sufficient data to back up its proposal, and argued that a study might indicate otherwise.

That prompted Annandale Supervisor Audrey Moore, who is pushing the fee increase, to respond: "There's an old political saying, when you've got the votes, vote. When you don't, study, study, study . . . The builders association has always objected to fee increases."

"What are we supposed to say?" shot back Robert Koury, president of the builders association: "Great! Double them?" Koury said he believed anyone hit by higher fees or taxes would demand to know the reason for the increase.

Under the Fairfax proposal, plan review and construction permit fees for a two-story "contemporary dwelling" would increase from $793 to $1,155. By comparison similar fees are $2,056 in Prince George's; $1,653, Alexandria; $1,134, Montgomery; $1,008, Prince William; and $984, Arlington. Only Loudoun, which charges $544, is lower than Fairfax.

Fairfax fees vary for town houses, high-rise buildings, restaurants, warehouses and other structures from $449 to $21,454. Most of the fees would increase an average of 50 percent if the proposal is approved.

Moore said the builders normally pass those costs onto home buyers, but she did not believe the increase would affect home sales.

When the county staff originally proposed increasing the charges to builders, they recommended that the fees cover 100 percent of the costs of reviewing and inspecting of new homes, and that those increases be raised over five years. The board opted instead for 65 percent.

Because of the recession and a sharp drop in home construction, the revenue raised by the higher fees only covered about 47 percent of department's costs, according to county officials. Deputy County Executive Denton U. Kent estimates that if the economy improves, the current fee structure would raise $5.7 million in fiscal 1984, enough to cover about 53 percent of the department's costs.