Amanda Bowers of Loudoun County is a working mother. By October, she may be a welfare mother, a victim of an overwhelmingly successful state program to help the working poor afford day care.

Demand for this year's $1.5 million subsidy that has helped Bowers and hundreds of Virginia parents meet expenses has so exceeded expectations that, according to local social service officials, the money will run out unless the state makes contingency funds available soon.

If the subsidy dries up in October, as expected, 55 parents in Loudoun County could lose funding for 92 children. In Prince William County, the figures are higher -- 65 parents with 100 children. In Alexandria, 159 families with 200 children are using the subsidy, but the city plans to subsidize day care for the current participants until next July, according to Jane Angrist, Alexandria child care coordinator.

"We are not taking any new families, and we'll have to stop the program entirely if more funding doesn't come through," Angrist said.

Fairfax and Arlington counties have participated in the program, but neither expects to end the service. Fairfax has funds to meet its caseload requirement, and Arlington will make up with local funds what it is losing in state subsidies, according to social service officials in those counties.

The day care subsidy, created with an appropriation of $3 million divided equally between fiscal 1987 and 1988, was designed to help parents, particularly single mothers, stay off welfare. It was set up in response to a survey by the state Department of Children showing a need for child care among the working poor and in partial response to cutbacks in federal day care funds, according to Donna Douglas, chief of the Bureau of Adult and Family Services in the state Department of Social Services.

An income eligibility requirement is set by the local jurisdictions within the state guideline of less than 70 percent of the mean family income in Virginia ($33,480 for a family of four). In addition, the program requires that the locality provide a 10 percent match. The payments for day care are based on what the family can afford.

Eighty-seven of the state's 124 local welfare agencies now participate in the program, in contrast to the 47 that participated in fiscal 1987.

The program started slowly because of difficulties meeting complicated state regulations, according to social service officials. In fact, when the General Assembly convened in January, far less than the $1.5 million appropriated for the program in 1987 had been spent. The legislature took back $500,000.

But in the meantime, demand for the program had grown and the appropriation became insufficient.

"By the end of fiscal '87, we were serving 780 families with 1,400 children, and spending at the rate of $200,000 per month," Douglas said.

According to Douglas, the state welfare department plans to present a letter to Eva Teig, Virginia's secretary for human resources, stating that an additional $1.5 million will be necessary for year alone.

The department plans to ask the General Assembly to appropriate $5.8 million for the program in fiscal 1989 and $6 million for 1990, according to Douglas.

The Prince William Department of Social Services learned of the impending shortage of funds in July, director Ricardo Perez said.

"We had geared up by then and were spending $25,000 per month," he said. "The state has allocated us $68,000 for the whole of '88. It's a really tragic situation. We've worked with these mothers to try and get them off welfare, and now many of them will have no choice but to go back on."

There is one spot of relief. The state Department of Social Services has $64,896 that was returned by jurisdictions that chose not to participate in the program. It will be redistributed to the participants.

But that may be too little too late for Bowers and other mothers like her.

According to Joan Linhardt, director of social services in Loudoun, the county needs $300,000 per year to subsidize day care for the families already in the program.

"If those families have to go on welfare, it will cost the state $465,000 in Aid to Families with Dependent Children funds and related services," Linhardt said.

Bowers, a mother of two, says she receives no child support from her ex-husband. If she loses her current day care subsidy, which pays the $135 weekly costs for two children at the Paxton Child Development Center, she said she will have to quit her job as a secretary at Southern Electric Co. in Leesburg to care for her daughters. That, she fears, will send her onto the welfare rolls.

Under Virginia law, according to Linhardt, an individual is eligible for Aid to Families with Dependent Children payments if one parent is absent, dead or permanently disabled and there is no source of income for the family.

The payments are then based on a state formula that takes into consideration the number of family members.

Bowers is no stranger to the welfare program, having been on its rolls while she participated in a state-funded job training program that led to her present job.

During that time, she and her family received $347 per month in welfare payments plus food stamps.

"And I don't want to do that again," she said. "I don't want to be dependent."

As for Bowers' children, Renee, 5, and Denise, 4, they love the child care center, according to their mother.

"Even if I had the money and could sit home all day, there's no way I could teach them all they've learned at the center," Bowers said.