Metro's budget committee recommended yesterday that the subway begin operating on Saturdays and until 11 p.m. weekdays starting next September.

"I think Metro is going to change the region," committee member Joseph Wholey said in pushing for the recommendation, "if people can visit friends, go shopping or go to the movies on it. But if we just operate it as a commuter railroad, that won't happen."

The subway now runs only on weekdays between 6 a.m. and 8 p.m.

A budget committee recommendation is usually approved by the full Metro board. But the question of weekend or night-time service has potentially strong opponents in both Washington and the suburbs because the subsidized cost of providing the service would total about $2.2 million. That subsidy would have to be apportioned among the local governments.

Viewed as a percentage of the total Metro operating subsidy for bus and rail, however, the cost of additional rail service is minuscule. The $2.2 million increase would represent 6.7 per cent of the proposed rail subsidy, and only 2.3 per cent of the proposed bus and rail subsidy combined.

Furthermore, under the instructions the budget committee gave to the Metro staff, there would be savings in bus operations if the subway hours are extended. That is because parallel bus service would be eliminated when the subway is operating.

The committee specifically decided not to recommend Sunday service, at least for the first year. "I think I would edge into this slowly," said committee member Cleatus Barnett. "Depending on how Saturday service worked, then I would think about going to Sunday."

That also leaves Metro wide open for another assault by the Redskin football crowd, which is clamoring for day-of-game service to and from Robert F. Kennedy Stadium.

At the moment, it is almost impossible operationally to provide the kind of service that would be necessary to bandle a surge of post-game riders. But by September, the Blue Line, which currently terminates at the stadium, will have been extended to New Carrollton and the operational constraints will have disappeared. There will be enough track beyond the stadium to stack up extra trains.

But the key issue for extended subway service will be cost impact on local budgets, not irate Redksin fans. Even though the percentage of increase in subsidy is small, there is enormous hostility from some governments to subsidizing the system because the subsidy comes from politically unpopular property taxes.

Dee Allison, the Prince George's County staff representative to the budget committee meetings, told committee members, "My jurisdiction objects to weekend service." There have been similar objections, less formally expressed, from Alexandria and Montgomery County.

The District of Columbia is also concerned about rising subway operating costs and is locked into an impossible fiscal planning position because its budget must be approved by Congress and Congress has declined to do so for the current fiscal year, which began for D.C. on Oct. 1.

The city is operating under a continuing resolution of Congress. That permits the District government to spend money at the same level as last year's budget, but allows no new programs or increases in old programs, such as bus and rail operating deficits.

"I have some problems with (evening and Saturday rail service)," said Jerry Moore, the D.C. City Council member on the budget committee, "because of the costs."

Metro's budget analysts figure that the average subway ride in fiscal 1979 will cost Metro $1.06 to provide. But the rider will pay an average fare of 47 cents, which presents only about 44 per cent of the total cost.

The percentage, however, is well in line with what other metropolitan rail systems are reporting. The country's other new system. Bay Area Rapid Transit (BART) in San Francisco collects an average fare of 57.4 cents, while it costs BART $1.88 to provide the ride.

That's 70 per cent subsidy from other sources. And the much-bally-hooed Hudson Tubes, run by the New York Port Authority, collect only 29.3 per cent of their costs from the farebox and subsidize the rest from other sources. The New York City subway gets 54 per cent from fares; Philadelphia's subway gets 57 per cent. These figures were provided by the American Public Transit Association and represent fiscal 1975 costs and revenues.

But almost all of those other systems have some kind of outside revenue that holds them up. BART is the recipient of a new sales tax; the Hudson Tubes are subsidized by the port authority's bridge tolls.

It is a condition of public transit that it does not operate at a break-even basis. Those cities or areas with high levels of service have, for the most part, found a way to pay for transit apart from the property tax.

But the promise of Metro from the beginning was that it would provide frequent trains and good high-speed service. If it is to win public support, it must do that - not just carry the commuter. "I believe in it and I support it," Barnett said.

"I think this is one of the most significant moves we can take," said general manager Theodore Lutz. Lutz had originally proposed weekend service in his budget draft.