Mayor Walter E. Washington has reopened an old controversy by asking Congress to let some new buildings in downtown Washington rise higher than the 130 feet permitted by a law enacted in 1910.

The mayor told a House District Committee hearing last week that he would permit 160-foot-high structures - generally 16 stories instead of 13 - in the city's traditional retail core, bounded by 6th and 15th Streets and by Pennsylvania Avenue and K Street NW.

The new limits would be applied obly to projects that are carefully planned, with those plans submitted and approved by city officials.

"Thisis a way of slowing the westward drift of downtown and assuring growth east of 15th Street, where we want it to be," Washington said.

The basic idea of his "bonus program," the mayor said, would be to reward developers with a greater profit potential for designing buildings with greater amenities - such as plazas, fountains and sculpture - as well as to encourage the creation of minority-owned businesses as tenants.

Moreover, he said, the proposed 160-foot limit would be absolute. None oof the so-called "warts" on the roofs, such as air conditioning and ventilating ducts, chimneys or elevator housings, would be permitted.

Washington prefaced his proposal with a prediction: "This is one area I think may promote a little controversy. I hope it will."

It did. Capitol Architect George M. White noted city planner Edmund N. Bacon, chairman David M. Childs of the National Capital Planning Commission and Rep. Stewart B. McKinney (R-Conn.), the District Committee's ranking minority member all either questioned or attacked it.

Among others who testified during the two days of hearings, only D.C. City Council Chairman Sterling Tucker and Metropolitan Washington Board of Trade president Foster Shannon, a real estate executive, supported it.

If all buildings were the economic answer, McKinney observed, then New York would be an untroubled city.

Childs, a prominent architect, said Washington's low building profile, with the Capitol dome and the Washington Monument rising visually above other structures, is an asset of value. Tourists often remark that this makes the capital different from other cities, he said.

Although the low-height restriction befan as a fire safety measure, it is now enforced as an esthetic restraint, according to Daniel H. Shear, the planning commission's general counsel.

Although the mayor recommended the selective increase in building heights, he did not submit any proposed legislation, which presumably will be prepared for later consideration.

Actually, the mayor noted in making his proposal, federal law permits 160-foot buildings along the north sid of Pennsylvania Avenue, soon to be redeveloped.His proposal would simply extend that right northward as far as K Street.

The hearings were scheduled by District Committee Chairman Charles C. Diggs Jr. (D-Mich) to get comments on a recent 416-page committee report entitles "Impediments to the economic, functional and esthetic development of the District of Columbia, the nation's capital."

In opening the first day of hearings, Diggs hailed it as "an historic undertaking," the first congressional overview of its kind since 1902. He spoke of "more specific hearings and investigations . . . a critical analysis of where the committee's emphasis ought to be placed, and perhaps some new directions for further investigations."

One interpretation, freely mentioned by sources both on Capitol Hill and at the District Committee is searching for a reason for continued existence now that home rule has removed much of its legislative purpose.

Del. Walter E. Fauntroy (D-D.C.) seemed to be suggesting this when, in an introductory statement placed in the hearing record, he cautioned Diggs that the hearings should not "be allowed to become an end in themselves."

The hearings produced much discussion of the Districts development patterns, finances, image and future potential, but nothing new in the way of legislative proposals for dealing with them, other than the height limit relaxation.

Shannon, the Board of Trade president, said "there needs to be a lessening of the parental role from the federal establishment to one of a partnership role." For business, he said, the city must "create an atmosphere of 'I want you here.' The big thing is to lay out the welcome mat."

Tucker, the city council chairman, said a one-sided business orientation in the city's affairs prior to home rule "left a residue of suspicion and overraction to any economic development project. Our first job is to make the point that economic development is not pro-business, but pro-payroll. Our second job is to make sure that this, indeed, becomes the case."

Both Tucker and Washington said the completion of the Metrorail system and findng a way to finance its operations stand high among the city's needs.