McLean Gardens, one of Washington's largest concentrations of mederately priced rental housing, has been sold for $30 million to a California builder who plans to convert its 725 apartments into condominiums.

The builder, Dwight W. Mize, said in an interview yesterday that the McLean Gardens apartments will be restored and modernized before being sold at prices ranging from the mid-$40,000s to the mid-$70,000s. One-third of the units in the complex of brick buildings will be reserved for elderly home buyers, he said.

Howard Friedel, director of management and operations for CBI Fairmac, the company that has owned McLean Gardens since 1972, confirmed yesterday that Mize has signed a contract with the company to purchase the complex. McLean Gardens is collection of low, redbrick apartment buildings scattered among trees on a grassy 43-acre tract between Rodman and Newark streets, 38th and 39th streets NW, a few blocks from the Washington Cathedral.

"We decided to get out of the rental housing business," Friedel said yesterday. "Mr. Mize feels that he can develop the property successfully, and we're very happy to let him try to do it."

McLean Gardens has been embroiled in tenant-owner controversies for years and tenants there have repeatedly fought off efforts by the complex's owners to convet the project into everything from condominiums to a diplomatic enclave.

The latest chapter in the continuing McLean Gardens tenants' and owners' saga began March 9 and 10 when Fairmac notified the 600 families renting there that the company had decided to cease renting apartments at McLean Gardens. As a result the company told the tenants, they had until Sept. 1 to move out.

Mize said yesterday that he has no control over what Fairmac has done.

Whether the tenants will have leave by Sept. 1 is still unclear, however. On Monday, Mayor Walter E. Washington signed into law an emergency bill designed to protect city apartment renters who are threatened with eviction because their building might be converted to condominiums. Under that law, all tenants are given an additional 90 days beyond their eviction date before they have to move.

Nonetheless, many of the tenants vowed once again to fight the latest effort to remove them.

James McCabe, chairman of the McLean Gardens tenants' association, said yesterday that a reporters' questions bout Mize's purchase and plans were "the first I've ever heard of it." It was "amazing. I don't know what to say," he said.

McCabe said that Mize's planned condominium prices "will price most of the current residents out. If there are people here who acan afford to pay $70,000 for a house, they would have done it long ago . . . I'd be damned if I'd pay $70,00 for two bedrooms."

Mize, who was in Washington yesterday to attend a White House dinner at which the employment of minority youths was to be discussed, said he plans to attend a community meeting tonight and discuss his plans with the tenants. He met yesterday with City Council member Polly Shackleton (D-Ward 3), whose ward includes McLean Gardens.

Shackleton said she is not yet sure if the conversion is a good or a bad idea. "I really don't know," Shackleton said. "I know everybody had always hoped that it (McLean Gardens) would never change. Whether that can happen with a piece of property like that, I don't know. Somehow, there's going to be some change, and I would hope that it would be something acceptable to the majority of the residents." Mize struck her as a "very agreeable man," she said.

Mize said he has put down a substantial deposit on the property - he declined to specify how much - and expects settlement to take place sometime in the next few months. Restoration and renovation are expected to take about a year-and-a-half, he said. Former residents will have first right to buy their old units or similar units, he said.

"If people fully understand that I'm trying to provide decent housing in a decent location at a reasonable price, then they can't do anything but support my efforts," Mize added."I'm a home builder. All I've ever done is provide housing for people."

The sale was put together by an agent of Town and Country properties who goes by the name of Basheyba. She is the same agent who was involved in the controversial sale of the Rockefeller estate here to a Washington developer who plans to build more than 100 homes on the 25-acre tract.

"What Dwight's going to do is in the best interests of everybody in Washington," said Basheyba. "He will save that housing. He will provide housing for middle and low income persons (in that area). You can't buy a house in that are for less than $165,000 that makes any sense."

Mize said each unit will have new wiring and plumbing, new ecologically protective windows, new heating, and central air conditioning, and service Porches will be installed. Each condominium also will have a new kitchen and it's own washer and dryer.

"It's a permanently built building," said Mize. "Frankly, it's built better than most of the buildings in California."

Friedel, of CBI Fairmac, said that about 450 apartments at McLean Gardens either now are vacant or their inhabiting tenants have notified the company that hthey plan to move.

Friedel added that about 300 of the families there have taken advantage of a relocation assistance being offered by Fairmac.

Under Fairmac's relocation program, tenants receive moving expenses ranging from $330 for an efficiency apartments to $390 for a two-bedroom apartment. Tenants who hire a licensed and bonded mover can receive up to $500 reimbursement if their moving bill exceeds those amounts.