A 34-year-old Springfield carpenter, seeking aid at the Fairfax County welfare office, has been unemployed since the end of November, trying to live on an unemployment check that is less than a quarter of his usual salary.

If he lived in Maryland, he could apply for welfare to supplement his unemployment compensation. If he lived in either Maryland or the District of Columbia, he could apply for welfare when his unemployment checks stop.

But because he lives in Virginia, the carpenter, his wife, and four children can receive little financial help other than food stamps - unless he leaves his family.

Virginia is one of 22 states that prohibit basic welfare payments to families where there is an able-bodied but unemployed father in the home. Families like that of the carpenter are not qualified to get Aid to Families with Dependent Children (AFDC) simply "because both parents are there," explained one Fairfax eligibility worker.

In the Washington area and throughout the country, welfare payments vary from state to state in size, requirements for eligibility and services offered. The average amount spent in Virginia for each person is $924. In Maryland, the amount is $1,643, and in the District, $2,016, according to a recent survey of the nation's five biggest welfare programs by the National Journal, a weekly magazine that covers federal policy.

Jimmy Carter made welfare reform one of his principal issues during the election campaign. He called on the federal government to assume responsibility gradually for the welfare system to eliminate inequities and lighten the economic burden on state and local agencies which now pay part of the cost.

Joseph A. Califano Jr., the new Secretary of Health Education and Welfare, is preparing plans to reorganize the welfare system. His job is to untangle the nation's more than 1,300 individual public assistance classifications. They range from AFDC - the depression-era program established to "insure" families against various forms of economic calamity - to Medicaid, the federal-state program that pays medicaid costs of the poor.

The vast disparities in state Welfare payments are particularly noticeable in the Washington area, where similar families living within miles of one another in the three local jurisdictions may receive different benefits - or none at all.

The differences in payments are hard to account for, Virginia, low in its average expenditure for each poor person, actually offers a higher average AFDC payment than Maryland. However, Virginia sets stricter eligibility standards for receiving aid, in some instances, than its neighbors and it puts ceilings on the amount that can be paid to a family - no matter what its size.

Alone, these differences in regulations between Virginia, Maryland and the District do not explain the disparities in payments. Many poor people in Virginia simply never apply for help.

A welfare study commission appointed by Virginia Gov. Mills E. Godwin recently discovered that 30 per cent of the state's population was poor enough to get Medicaid payments in fiscal year 1974-75, but only 8 per cent of the population received them. Part of the difference was due to persons who qualified because of income but did not have the necessary "welfare link."

In other words, if a family did not qualify for AFDC, in many instances, it could not receive other monetary help, either.

"The state's system is effective as far as it goes," said Human Resources Priorities Commissions vice chairman Sheila Doud of Alexandria. But there is far too much paperwork . . . Money needs to be set aside for those people who don't fit in because they aren't perfect in their poverty."

Wendy Church of communications office of the Virginia welfare department, said there could be a number of reasons why Virginia pays less per poor person than some other jurisdictions.

Church said the main reason probably is the decrease in the welfare caseload brought about at least partly by Virginia's aggressive antifraud and "support enforcement," programs. The "support enforcement" program requires mothers who wish to receive public assistance, claiming desertion, to help track down absent fathers and testify against them in court if they refuse to pay. Maryland and D.C. have similar programs, but Church said the operation in Virginia may be more effective.

"We suspect that's what's happening, but it's difficult thing to prove, of course," she added. Officials of fraud and support of enforcement programs in Maryland and the District contended that their units also are effective, however.

Church also noted that many people who qualify for food stamps in Virginia do not apply for them. They do not realize the savings the stamps represent, she said. The stamps are available to the poor under a federal program with a single nationwide eligibility standard.

In addition, she said, Virginia has a large rural population, which may make payments lower.

All states that participate in the Medicaid program (Arizona has not up to now) must provide certain services for families which receive AFDC funds. In addition, each state has the option of providing a variety of other services to persons who are medically needy but don't receive other financial help. D.C., Virginia and Maryland all provide the latter, but again, there are differences.

For example, Virginia and D.C. both provide Medicaid for physical therapy and related services; Maryland does not. The District offers help for youths in psychiatric hospitals; Maryland and Virginia do not.

A spokeswoman for Maryland's Department of Human Resources said the families of unemployed fathers are eligible for nearly all welfare services, subject to some restrictions. In D.C., the families of unemployed fathers also qualify for the same services availabe to other AFDC homes.

In Virginia, such a family may be able to get food stamps, but little else is available.

The Springfield carpenter, whose employment prospects have been severely curtailed by the unusually harsh winter, has not paid his utility bills or his car note in two months, and is a month behind in his rent. His unemployment checks have been used for food stamps and a portion of the rent - "You've got to have a place to sleep and things to eat," he said.

Virginia's Human Resources Priorities Commission made no estimate of the cost to taxpayers of a program providing payments to families of unemployed fathers, but a state welfare department spokesman said it would be a "fairly high amount of money."

In fiscal year 1976, the cost of such a program in Maryland was about $5 million, and about 8,000 residents were helped, according to a spokeswoman for Maryland's Department of Human Resources. In the District, 1,159 persons are aided through the AFDC-Unemployed Fathers program.

Bertrell Hallum, administrator of the payments assistance administration in the District, said that during the month of December more than $89,000 was paid to such families.

"Obviously, we feel very strongly about it," Hallum said. "Our primary concern obviously is to keep families together . . ."

In Virginia's counties and cities that can afford it, a poor family in which there is an unemployed father may qualify for special payments under general relief or emergency assistance programs.

"A lot of them (localities) don't have it," said Church of Virginia's welfare department communications office. "And a lot of them had the money in July, but by the end of the year are running out. Many have a program but no money in it."

Church said rules governing the general relief payments are "pretty strict - in many areas, the parent would have to be incapacitated."

Edward Amundson, deputy director of Fairfax's Department of Social Services, said that in most instances the county's general relief payments are "kind of a one-shot deal" resembling the emergency assistance program. Most of the money is available for unemployable persons, he said. He estimated that there are fewer than five cases a month in Fairfax in which aid is given to the families of unemployed fathers.

All 50 states and the District make determinations of what a family with no income of its own needs to survive.

Many states, in trying to compute this figure, set standards that are "unrealistically" low, and then further compound the problem by not granting payments equal to 100 per cent of that established need, according to Elizabeth Chief, a welfare specialist with HEW's Assistance Payments Administration.

Part of the problem, Chief said, is that in the past officials "emphasized reductions and dwelt on fraud," rather then trying to improve services.

Chief worked 16 years with a regional welfare agency in which she learned about welfare systems in Virginia, Maryland, and D.C. All needed improvements, she said.

"I was appalled at the services available," Chief said. "I called them disservices."

Virginia and D.C. pay about 90 per cent of the "survival" standard each has established (except for Fairfax and Arlington Counties, which pay 100 per cent of need). Maryland pays about 77 per cent.

This means that though Virginia feels a rural family of four needs $272 a month to live, it would only get $245. In Maryland, the Department of Human Resources calculates that a family of four gets $242 a month to live, about 77 per cent of the money needed. Similarly, in the District, a family of four can receive $314.10, about 90 per cent of the minimum needed to live.

The three jurisdictions determine the size of payments in different ways. In Virginia grants vary depending on which section of the state the recipient lives . . . For example, a family of four with no other income living in rural Virginia could receive $245, while the same family could get about $311 a month in Northern Virginia. A rural family can receive a maximum of $305, regardless of family size. Maximums also are set for Northern Virginia and large cities.

Maryland and D.C. both base payments on family size. The larger the family, the more money it con receive Maryland has one basic payment standard and does not take into consideration where in the state the recipient lives, accoding to Linda Schulte of state's Department of Human Resources.