The Sterling Commuter Bus, a nonprofit service taking Loudoun commuters to Washington and back home each day, is losing about $1,000 a month and may have to curtail or halt operations, its organizers say.

The organizers have asked the Loudoun County Board of Supervisors to provide county money to cover the deficit, at a time when the county government is considering belt-tightening measures to cope with its own expected budget shortfalls this year and next.

The Sterling Commuter Bus currently carries at least 60 people a day on two coaches. During the energy crisis in the 1970s, ridership was three times as high, and patronage has continued to diminish this year. As a result, the daily charge was recently increased from $5 to $7.

On Aug. 7, at the Board of Supervisors' last meeting before its August recess, Supervisor Howard P. Smith (D-Sterling District) asked the county administration to look into the bus system's request, noting that its current contract with the Purcellville-based Virginia Coach Co. ends in late September.

The county staff is expected to report back to the board next month. The county is subsidizing pilot recycling programs with comparable amounts of money, however, supervisors gave little indication of their inclinations to help finance the bus system.

"It's very difficult" to find the best solution, Supervisor Steve W. Stockman (R-Broad Run District) said at the meeting.

Loudoun has virtually no public transportation, and county officials say they don't anticipate putting money into Metro or their own bus system in the near future.

In addition to the Sterling buses, about a half-dozen regularly scheduled van-pool round trips are made daily by a private group taking passengers between Round Hill and the District, according to Eric Vogel, chief of the transportation division of the county's Office of Technical Services.

Vogel said the county government is spending about $70,000 a year promoting alternatives to one-person automobile trips, including a service that matches potential car- and van-poolers, but he said no statistics are available on how many such pools exist in Loudoun.

About $240,000 in local gas tax revenue has been set aside toward the estimated $375,000 needed to build a 150-space park-and-ride lot in the Cardinal Glen subdivision, just north of Route 7 in Sterling. That facility, which could be used by bus, car pool and van pool riders, would be the first such lot in the county.

Yet even if all goes well, it will not open for at least two years, Vogel said. And some Cardinal Glen residents have voiced concerns about a heavily used park-and-ride lot in their midst.

It's unclear what the impact would be if the Sterling Commuter Bus service cuts back to one coach a day, raises fees dramatically, or ceases operations. Bus system organizers and county officials say there has been an increase in car and van pools in Loudoun in recent months, which may have taken ridership away from the bus service. But some eastern Loudoun residents could be left in a lurch, and more people might jam the roads with their cars.

"Some people have one less vehicle" at home because they count on the Sterling bus service, said David Hobbs, an organizer of the operation. "If we go out of business, it's a real problem."

Hobbs said the Sterling system is paying its bills about a month late because of its deficit. It costs roughly $10,000 a month to put the buses on the road, but revenue has been lagging by about $1,000 a month, he said.