The House District Committee has switched from its previous six subcommittees to three broad ones to oversee city affairs.

Rep. Herbert E. Harris II (D-Va.) was named to chair an Economic Development and Regional Affairs Subcommittee that will be considering proposals for a Civic Center as well as such regional matters as rapid-transit and water and sewer systems.

Rep. Ronald V. Dellums (D-Calif.) will head a Fiscal and Government Affairs Subcommittee that will be primarily concerned with the District's financial problems and desire for greater home rule.

Rep. Romano L. Mazzoli (D-Ky.) will be the chairman of a Judiciary Subcommittee that will oversee the local courts and other legal matters.

D.C. Del. Walter E. Fauntroy (D) passed up the opportunity he had to be a House District Committee subcommittee chairman so that he could serve instead as chairman of the House Banking Committee's little known Historic Preservation and Coinage Subcommittee.

Fauntroy, who remains a member of the Historic District Committee, has said heading a Banking subcommittee puts him in a better position to help other congressmen and, in return, seek their help for the District.

However, in its two year's existence the Historic Preservation and Coinage Subcommittee has considered only about 50 bills on two dozen different matters relating to the printing or minting of the nation's money, only two or three of which became law.

It has considered no legislation relating to historic preservation, where its authority is limited to what he Department of Housing and Urban Development is doing in that field.

The reorganized House District Committee headed by Rep. Charles C. Diggs Jr. (D-Mich.) now has 20 members (13 Democrats and six Republicans). Rep. Stewart B. McKinney (R-Conn.), sponsor of the so-called commuter tax in the previous session, is the ranking minority member. The committee has 44 employees.

"We consider the committee's jurisdiction to be one of partnership with the local government. Our main purpose is to protect the federal interests," said Diggs at the organizing meeting.

Harris said he enthusiastically accepted his subcommittee chairmanship because it will enable him to continue his work over the years in pushing for regional responses to the Washington metropolitcan area's problems.

Democratic members of the House District Committee are, in order of seniority: Reps. Diggs, Dellums, Fauntroy, James R. Mann (S.C.), Mazzoli, Harris, Dan Daniel (Va.), Helen S. Meyner (N.J.), Fortney H. Stark (Calif.), Charles Rose (N.C.) Norman E. D'Amours (N.H.) Ted Risenhoover (Okla.) and Douglas Applegate (Ohio).

Republican members, by seniority are: Reps. McKinney, Robert W. Daniel Jr. (Va.), Charles W. Whalen Jr. (Ohio), E. Thomas Coleman (Mo.) Mart L. Marks (Pa.) and Newton I. Streers Jr. (Md.).