During the grueling budget debate, members of Congress had a lot on their minds - like whether to cut medical care for the elderly or day care for infants, and, by the way, where to put their new tennis court.

The Senate already has a tennis court in the Dirksen Senate Office Building. But the poor members of the House don't have any place to practice their ground strokes on the taxpayer's dime.A few members of Congress decided it was time to remedy the situation. They have ordered the architect of the Capitol to draw up plans for a House tennis court, either in the courtyard of one building in the complex or on the roof of another.

Congressional sources told us that Rep. Stephen Solarz, D-N.Y., led the pack. A spokesman for Solarz confirmed that the congressman had been involved in meetings about the tennis court.

"All through this there has been a general assumption that if they went ahead with this, no public funds would be used," the spokesman said. But Solarz's office offered no explanation of whose pockets Congress would dip into for this little gift.

Maybe they expected a donation from a generous corporate constituent - no strings attached, of course.

Solarz may not have planned to stick the taxpayers with the bill, but public money has already been spent on the project - design time in the office of the Capitol architect George White.

The tennis court, which would have to be approved by the House leadership, could go in the courtyard of the Cannon House Office Building, or on the roof of the Madison Building of the Library of Congress.

The Cannon building is close to the Capitol and conveniently accessible to all the House offices by a network of underground tunnels, but the sound of balls being lobbed back and forth could be distracting to office workers. The Madison roof would be more spacious, but then the architect would have to deal with the problem of balls flying off the roof.

White, whose full-time job for the past 20 years has been keeping up with renovation and new construction in the Capitol complex, told us the tennis court isn't the first controversial order he has received. He is obligated to respond with designs when members of Congress make suggestions.

White characterized the tennis court as "the pipe dream of a few tennis players." Solarz has a history of mixing business and tennis. In 1983 we obtained State Department cables explaining to U.S. Embassies how Solarz expected to be treated on a trip to Latin America. "Tennis courts are an important plus . . . Solarz would like to play tennis every day if possible . . . assistance in arranging court and securing high-quality tennis opponents will be appreciated," one cable said.

White hasn't generated cost figures yet on Solarz's latest request, so we asked a tennis court builder for a guesstimate. A basic asphalt court would cost about $28,000. And for those late-night sessions, it would cost another $8,000 to light the court.

Putting the court on the roof of a building adds unknown costs depending on how much work the roof would need to support the court. And then there is the federal factor. That's the line item on the bill where the contractor doubles the price because this is government work.