D.C. Council Chairman Linda W. Cropp (D) yesterday called for new ways of paying for Metro, saying the District cannot afford the increasing costs of the aging transportation system.

Cropp suggested instituting a regional tax, increasing the federal government's share of funding or renegotiating the current funding agreement, which requires the District to pay slightly more than Maryland and much more than Virginia.

"We're willing to pay our fair share, but not more than our fair share," Cropp said. "Metro will eat us alive."

Earlier this year, a 13-member regional panel brought together by the Metropolitan Washington Council of Governments, the Greater Washington Board of Trade and the Federal City Council recommended raising sales taxes in each of the jurisdictions as much as 0.5 percent to pay for Metro cars, buses and other needs. Officials in Washington, Virginia and Maryland responded coolly.

In the current fiscal year, the District is paying 37.5 percent of the system's operating expenses, Maryland 37 percent and Virginia 24 percent, according to Metro. Over the next five years, the District's capital plan includes $436 million for its share of Metro investments, second only to the $715 million budgeted for city school construction and renovation. The city's current contribution to Metro's operating budget is $164 million.

Although tax revenue is strong in the District, thanks to a robust economy and real estate market, Cropp said she is worried about the long-term ability of the city to afford its Metro obligations. Borrowing is not the answer either, Cropp said. The D.C. government already has the highest amount of debt per person in the nation, according to the city's chief financial officer.

Disputes over the fairness of Metro's complicated funding formula are hardly new. The Metro board looked at the funding formula several years ago, but no major changes were made, according to Candace Smith, a Metro spokeswoman.

Council member Jim Graham (D-Ward 1), who represents the District on the Metro board, said he shares Cropp's frustration over the amount the city spends on Metro but said renegotiating the funding formula would be nearly impossible politically.

"If one party gains, another will lose,'' Graham said. "There's a greater likelihood of getting a regional tax than renegotiating, and it's going to be very hard to get a regional tax.''

Several studies of Metro's finances stressed the importance of securing a dedicated revenue stream for the transit system that is insulated from the yearly political and budgetary pressures of its separate jurisdictions.

Last year, a Brookings Institution study found that Metro is facing a financial crisis because it is the only major transit agency in the country without a significant source of dedicated funding. Systems in New York, Boston, Chicago, San Francisco, Philadelphia and elsewhere are guaranteed a portion of a gas tax, sales tax or some other revenue to help pay their costs, but Metro has to plead for financial aid each year from the District, Virginia and Maryland.

Robert L. Flanagan, Maryland's transportation secretary, said yesterday he shared Cropp's concerns about the rising cost of Metro. He said better management and efforts to rein in spending would be prerequisites to any meaningful discussion of increased funding.

Cropp said the federal government should also pay more to keep up Metro. Almost half of the subway riders during peak hours are federal employees, and more than 50 federal agencies or work centers are located next to Metro stations.

Metro's operating costs are projected to exceed $1 billion in the fiscal year that starts Friday, a nearly 50 percent increase in six years, according to the agency. Metro receives subsidies from the communities it serves and yearly allotments from the federal government to buy big-ticket items such as rail cars and buses. Those subsidies, plus passenger fares, advertising and other revenue pay for the system's operating costs.

Metro funding is based on the number of stations in each jurisdiction, which is why the District pays the most, Smith said. If the system is expanded to Dulles International Airport, Virginia will pay the greatest share, she said.