A recent Supreme Court ruling forcing state and local governments to adhere to federal wage and hour laws will add $10 million to $15 million a year to the costs of operating the D.C. government and hundreds of thousands of dollars to suburban governments, area officials say.

That is only a small portion of what is now estimated to be the overall $2 billion to $4 billion cost to state and local governments from the ruling that forces the governments to pay overtime wages to most of their workers instead of giving them compensatory time off.

"It's too much money," complained attorney Gilbert J. Ginsburg, a labor lawyer who is an adviser to many cities, including Alexandria and New York.

The ruling "hits very, very hard and is a burden," said Cornelius J. O'Kane, Fairfax County's personnel director. Officials there estimate the court's Feb. 19 ruling will cost Fairfax taxpayers $500,000 to $1 million a year.

Most of the added costs will come in overtime to police and firefighters, who in the past have earned substantial amounts of compensatory time off.

For example, one immediate impact of the ruling is in western states such as California, where thousands of firefighters will be collecting time-and-a-half overtime pay for battling the forest fires that were out of control in that region last week. Paying the California firefighters overtime wages, rather than compensating them with time off later, will cost $10 million to $20 million, according to James D. Mosman, the state's director of personnel administration.

Cities, which are expected to be hit the hardest when the Labor Department starts enforcing the court ruling Oct. 15, are raising the possibility of layoffs, reduced services or higher taxes. Officials in the Labor Department and the White House say they have been flooded with calls and letters from mayors worried about the impact of the ruling on their budgets.

Local governments attacked the ruling when it was announced, but say they are only now beginning to add up the likely costs as their budget and personnel officers supply them with more precise estimates.

"We are just now getting a handle on it, and it is very difficult," said Donald Weinberg, the District's director of labor relations. "It is causing a real problem."

District officials say the impact of the ruling here will not be as severe as in some other large cities because Washington already pays overtime to many of its employes. "If there are no other pressures then it is clearly manageable," said Betsy Reveal, the District's budget director. "But it cannot be seen in isolation. In combination with other pressures it could cause problems." The District's annual payroll is about $850 million.

Under guidelines for the Fair Labor Standards Act, which state and local governments now must follow, police must receive overtime pay if they work more than 171 hours in a 28-day period. For firefighters, overtime must be paid after 212 hours.

Blue-collar employes in public works as well as clerical and technical employes, many of whom commonly work overtime hours, would also be covered. Teachers, as professional employes, are excluded from coverage under the law.

The Supreme Court rulng came in a case known as Garcia v. San Antonio Metropolitan Transit Authority on the question of whether overtime provisions in the act apply to municipal workers.

Joseph Garcia, a bus driver in San Antonio, had brought suit against the city, challenging its practice of paying time-and-a-half overtime only when bus drivers worked on their days off or on holidays. For all other overtime hours worked, bus drivers were paid at the normal hourly rate. The city said it should be exempt from the act; Garcia, backed by labor unions, said it should not.

The 5-to-4 high court ruling has diverse implications. For example:

*Municipalities will no longer be able to accept volunteer or subminimum wage services from their employes. Crossing guards -- frequently senior citizens working for little or no pay -- will have to paid at least a minimum wage, for instance. This provision is expected to hurt small towns, which frequently depend on volunteer workers to a large degree.

*Municipalities may have to pay substantial sums of overtime wages to police recruits in academies who devote long hours to their training. "We've heard of an instance where trainees are paid at a higher rate than police captains," said a White House official. The official, who asked not to be identified, said the likely effect in that instance would be a cutback in training time for police officers.

*Public employes in some rural jurisdictions who saved compensatory time by working long hours in the winter so they could plant their crops in the spring will be unable to continue that practice.

*In Puerto Rico, implementing the act is expected to cost millions of dollars because the government must start paying the minimum wage to public employes who have been earning less.

Officials also express fears of curtailed work by public safety employes, and cite the case of four D.C. homicide detectives whose investigation of a murder was cut short last week to avoid paying them overtime. The incident occurred shortly after police officials had circulated a memorandum outlining steps to comply with the ruling.

"There's an increasing degree of alarm about the costs and the disruption, both of which will be substantial," said the White House official.

Congressional hearings on the issue are scheduled for July 25, and three governors as well as a host of local officials are expected to raise the prospect of budget-busting expenses because of the ruling.

Groups such as the National Association of Counties and the National League of Cities also are increasing pressure on the Reagan administration to introduce legislation that would repeal overtime provisions of the Fair Labor Standards Act and effectively neutralize the fiscal impact of the Supreme Court's ruling.

The White House official acknowledged that the administration is considering backing such a bill. Congressional aides say the measure would be opposed by organized labor, and would stand little chance of passage in the Democratic-controlled House of Representatives.

"What happens on the House side depends on how much pressure we can gin up," said one Senate aide who would like to see the Garcia decision undone by Congress. "But politically I just don't think we can do it."

Susan Meisinger, deputy undersecretary for employment standards in the Labor Department, said she believes legislation is possible. "There's a growing concern about the impact," she said. "What happens depends on how hard state and local governments push."

In a speech to the American Bar Association last week, Attorney General Edwin Meese III blasted the court for the Garcia ruling, declaring that it "undermines the stability" of state and local governments.

To comply with the ruling, Los Angeles will have to pay $100 million a year; San Francisco, $50 million, and New York, $40 million, according to Cynthia M. Pols, counsel to the National League of Cities.

Many municipalities are in the process of determining how many of their workers are covered by the federal guidelines and how many are not. Some personnel officials acknowledge privately that in borderline cases where there is room for discretion, governments may tend to classify workers as exempt from the law, and therefore ineligible for premium pay.

State and local government officials also are afraid of the effects of a provision in the federal law that allows employes to bring private lawsuits to recover back overtime pay. Because the court's ruling was effective April 15, any municipal worker who wants to collect overtime since that date will be able to do so, along with a penalty doubling the overtime payment. Ironically, although labor union officials initially were elated by the Supreme Court decision in February, some are now acknowledging that their members are unhappy about losing compensatory time off.