The move by Fairfax County Sheriff Stan G. Barry to charge jail inmates $1 a day for room and board has already raised more than $100,000 in the first seven months, officials said.

The General Assembly last year authorized Virginia jailers to assess a fee not to exceed $1 a day to help defray the cost of running a jail. Fairfax officials, who began imposing it in February on prisoners who stay more than two days, said they hope the charge will contribute about $200,000 annually to the county's general fund.

"If any place should have a user fee, it should be the jail," Barry said.

Jail officials estimated that it costs them about $125 a day to house a prisoner, so a $1 fee does not make a huge impact. By going into the general fund, which pays for almost all county programs, the money collected will not necessarily be returned to the sheriff's office or jail. The county already pays about two-thirds of the sheriff's $48 million annual budget, with state funds picking up the rest.

"This is our way of letting the citizens know we are conscientious with their tax dollars," said Capt. Karen McClellan, a spokeswoman for the sheriff's office. "We are trying to run a good operation, and we're not taking the money, we're giving it back to the system."

In the seven months the $1 fee has been collected, the average stay for an inmate has been just under 22 days, Capt. Katherine Little said. Prisoners land in the Fairfax jail for a variety of reasons, including serving short sentences for misdemeanors or minor felonies, awaiting trial on felony charges and awaiting transfer to prison after being convicted.

Although Virginia limits the fee to $1 a day, other states allow charges as high as $20 a day, Little said. Some also charge a booking fee of up to $65.

The Fairfax levy is automatically deducted from inmates' accounts once they have stayed for more than 48 hours. More than 60 percent of those who are booked into the jail are released before 48 hours elapse, Little said. Prisoners who volunteer for work detail are not charged the $1.

Currently about 1,230 prisoners are housed in the jail, many in crowded cells because the sheriff has not been able to hire enough deputies to staff large sections of a brand new wing of the jail. The population has risen as high as 1,350, Little said.

County officials have said they are apprehensive that the prisoner count will rise sharply after a state law took effect July 1 mandating jail time for drivers convicted of having a 0.15 blood-alcohol content. Fairfax Board of Supervisors Chairman Gerald E. Connolly (D) criticized officials in Richmond for "once again making the local taxpayer bear the lion's share of the costs" from a new law. "At some point, the state has to step up to the plate," Connolly said.

In the meantime, the county is seeking to fund 16 new positions in the sheriff's office for each of the next three years, Connolly said, in hopes of opening some of the vacant sections of the jail. "We have no choice," he said.