Loudoun County officials are moving to toughen their zoning ordinance in hopes of cracking down on people operating car repair businesses at home, and Fairfax and Prince William County officials say they may follow suit.

Prince William officials say that of the 70 to 100 active zoning ordinance complaints they are working on at any one time roughly a third are about car repairs or junk cars in residential neighborhoods. Loudoun's zoning office reports a similar figure while Fairfax County's zoning enforcement branch says the majority of its complaints are car-related.

While the zoning ordinances in Prince William, Loudoun and Fairfax counties vary slightly on the issue of home car repair, all three allow a resident to fix his own automobile on his own property as long as the car has a current license and an annual inspection. All three jurisdictions make it a zoning code violation, however, when a resident operates a car repair service out of his or her home and money changes hands.

Zoning officials say that, even if money isn't exchanged, it is a violation of the zoning code if repairs are ongoing, or noisy machinery is being used, or if there are inoperable cars sitting around the property.

"In between, there's sort of a gray area," said Sager William, Prince William's zoning administrator. "Two teen-agers can get together and work on each other's cars, but if it is done late at night with the radio blaring, then we will come by and check it out."

County officials say that, with the slow economy, which has tightened the job market and discouraged new car buying, the ranks of people operating car repair businesses out of their homes have swollen, precipitating a flood of complaints from neighbors unhappy with what they say is the accompanying noise, fumes and junk.

"We have one case where the guy has an air compressor going all the time," said Loudoun County Supervisor Betty Tatum (D-Guildford.) "The neighbors can't open their windows or have a cook-out for all the noise. With the ordinance we have, we can't really do much about it."

Tatum, who said the situation in the Sterling Park area of her district has gotten unbearable recently, asked the Loudoun zoning staff three weeks ago to propose changes in the zoning ordinance to better control what goes on with cars in residential neighborhoods.

But Loudoun's zoning administrator, Michael Congleton, said he canvassed Northern Virginia jurisdictions looking for suggestions and none could give him any help.

"Without substantial evidence that money is changing hands, a successful prosecution in court is highly unlikely," said Congleton. "We're looking into it again, but I don't know what we will come up with."

Despite the persistence of the problem, it is rare for a case to go to court primarily because it is difficult to prove whether the repairs one man is making on another's car is a business being operated out of a driveway or just one guy doing another guy a favor.

In one instance, Prince William County has filed a suit against a county resident in an effort to force him to remove 10 inoperable cars from his property, said County Attorney John Foote. He said it is the first such suit he can recall his staff filing in recent years.

"The neighbors, who are quite upset with the problem, have become our best witnesses in this case. They have kept logs of cars coming and going, and taken license plate numbers," said Sager Williams, Prince William's zoning administrator. Virginia state Del. Floyd Bagley, attorney for the man, denies that his client is running anything resembling a car repair business. "If someone asks him for help with their car, he'll give it to them, that's all," said Bagley.

Loudoun County officials say they are looking at the possibility of rewriting their ordinance to prohibit repair of any automobile not owned by a property owner, an act that is currently not expressly forbidden.

"We want an ordinance with teeth," said Loudoun's Supervisor Tatum, "But it's going to be difficult to do without infringing on anybody's rights."