The D.C. City Council voted yesterday to let elderly persons with annual incomes of up to $30,000 continue to rent their apartments for the rest of their lives when their buildings are converted to condominiums.

The liberalized income limit was added to a bill that would strictly regulate condominium conversions in the District. The bill received preliminary approval from the council yesterday in an unrecorded but unanimous voice vote. Final passage could come in two weeks.

A key provision of the bill would permit future condominium or cooperative conversions only when a majority of tenants in a building approve it.

The original version of the bill, introduced by John A. Wilson (D-Ward 2) and eight others, would have provided lifetime rentals only for two low-income elderly tenants -- those with incomes ranging from $8,879 for an individual to $17,757 for the head of a household of four. An elderly person, as defined by the bill, is at least 62 years old.

Wilson moved to raise the income ceiling because of complaints from many of his center-city constituents that they would be squeezed out if their rented apartments were converted because their incomes are too high.

Wilson's amendment was adopted on a voice vote without debate.

Reaction to the council action predictably was mixed.

Mark Looney, speaking for the Citywide Housing Coalition, a sparkplug of the condominium regulation bill, said his group was "very pleased by the outcome," and especially by the $30,000 income ceiling.

But G.V. (Mike) Brenneman, a leading condominium developer and frequent spokesman for the industry, said his mind "boggled" at word of the council action.

"People with that kind of income can obviously take care of themselves economically," Brenneman said. "I am just obviously amazed. It must be election year fever."

Wilson, sponsor of the amendment, is running for reelection in November.

James G. Banks, executive vice president of the Washington Board of Realtors, said the lifetime rent requirement could imperil financing for some condominium conversion projects, because it would decrease the income developers could expect.

Although condominium conversions have been regulated to some degree in the District since 1974, the rapid increase in conversions became a major political issue last year when the council imposed a temporary, but near-total, moratorium on them.

The moratorium will expire in August, when provisions of the pending bill are expected to take effect.

Before the moratorium was imposed, landlords were permitted to convert so-called high-rent units without significant restrictions. Conversions in low-rent projects, however, required tenant approval.

As a result, conversions have been concentrated in neighborhoods that ring downtown or are west of Rock Creek Park.

Yesterday's debate on the bill lasted nearly three hours, mostly spent on technical amendments. The council voted 6 to 3 to retain a proposed 4 percent tax on the value of condominium sales to finance housing assistance for displaced low-income families.

In other matters yesterday, the council:

Voted to close a T-shaped alley in the downtown block occupied by Garfinckel's department store, clearing the way for a redevelopment project by the Oliver Carr Co. that will include removing the historic Rhodes Tavern at 15th and F streets NW. Final action is scheduled June 17.

Enacted permanent legislation providing for licensing private colleges and universities in the city, replacing emergency legislation that had been enacted for 10 consecutive 90-day periods since 1977.

Gave preliminary approval to seven other permanent bills that will replace current emergency legislation. The council's use of emergency powers was restricted by a recent court decision.

Gave preliminary approval to a bill to assess utility companies for the $800,000 it costs the D.C. Public Service Commission to regulate them each year. Those costs are now covered by general public taxation.

Gave preliminary approval to a bill to tax savings and loan associations chiefly on the basis of their net incomes rather than their gross earnings.