Residents who have dumped their garbage for free at the county's landfill will face a choice Aug. 1: Pay $5 to get rid of the trash or bring a bag of something to be recycled.

Charges for services such as trash dumping or zoning permits are called user fees, and Loudoun, like most places, is moving toward this means of generating income.

"The whole concept behind user fees in local government is that a lot of services are directed at particular groups of individuals, and those people should pay for those services instead of using general revenues," said Kirby Bowers, of the Loudoun budget office.

Among the county's user fees are charges for maps, sewage licenses and after-school care at county schools.

"It's clear that this {landfill fee} is an item that we can figure out how much the cost is and reasonably charge back to the users," said Supervisor Steve W. Stockman (R-Broad Run).

"To the extent that we can identify costs, and if there's no social reason that the county should pay for a service, then the users should be the only people required to pay for it," Stockman said. "That's a way of keeping your property taxes down . . . . It's more toward privatization, except the county's collecting the money."

Although the fee will be waived if residents bring a bag of recyclable material -- newspapers, cans or bottles -- the county is counting on making money from the charge.

"The reason we went to the householder fee is that our estimate is that we are still running a deficit in operating the landfill," said Terry Wharton, director of the county engineering department. "The board dictate has been, for several years, that the landfill become self-sufficient."

It costs Loudoun $3 million a year to operate the landfill, and Wharton said the user fee and the increased fee for commercial users should cover costs. In 1989, residents made 43,000 visits to the landfill, dumping 25 percent of the landfill's trash, officials said.

Generally, the new fee will affect those who live in single-family houses who do not employ private haulers. Private trash collection contractors that serve large subdivisions and incorporated towns will be charged $40 for every ton of garbage, up from 1989's $29-a-ton rate.

"I think the Board of Supervisors is concerned with the county's real property taxes, and to the extent that they can expand the tax base, they want to do that," Bowers said. "That's the whole philosophy behind user fees."

Many of the fees the county charges involve land development. Things like real estate inspections, well installations and grading permits carry a price, and officials say prices go up if the income doesn't pay for the services rendered.

"I think the plan now would be to look periodically at user fees," Bowers said. The fees will be adjusted if the income generated is not sufficient for the costs of the program.

"It's simple mathematics," Bowers said. "You take the cost of the program and decide how much you want to bring in with fees."

In the case of the landfill, officials are not certain whether the fee will have to go up again to pay for maintenance. "If it's too high, then people will drop their stuff on the side of the road," Wharton said. "But $5 will keep 80 to 90 percent of the people coming in."

Though the projected landfill income has been figured into the county's 1991 budget, the Board of Supervisors will hold public hearings on Monday about an additional $335,000 in expected revenue from other fees. Most of those fees involve land development.