Nearly 30,000 former homeowners across the country -- and as many as 150 in the Washington area -- who lost their federally insured homes through foreclosure are now eligible for a government review of their cases. If successful, they may be able to get back their former homes or obtain substitutes.

Many of the foreclosures were the result of temporary financial problems such as a homeowner's sickness or loss of job and could have been avoided, according to lawyers familiar with the cases.

The reviews are made possible when a federal judge in Chicago approved settlement this month between the Department of Housing and Urban Development and legal services attorneys requiring HUD to reconsider its rejection of thousands of requests for help to avoiding foreclosure.

The period covered by the settlement was from May 1976 through January 1979 and involves people whose homes were insured with Federal Housing Administration loans.

HUD also will review the cases of former homeowners who never applied to HUD for help because their lenders never told them that assistance was available before foreclosure. Some of these people may also be eligible to get their homes back.

Through the FHA program, HUD insures mortgage loans against default. In 1976, a special program was established by HUD to help families avoid foreclosure. If a family falls behind in its payments to the lender, HUD may be asked to review the case ns decide whether the agency wants to buy mortgage from the lender and help the family find ways to make payments. If HUD rejects the case, then the lender can foreclose, and the property is sold to HUD.

The legal services attorneys, contending that the aid program had not worked, filed suit late in 1977.

"HUD totally failed to properly run the program," said George Gould, an attorney with Community Legal Services in Philadelphia. "We alleged that they just completely ignored their own regulations and their procedures and illegally rejected a large number of people under the program."

Consequently, he said, thousands lost their homes needlessly.

One local person who could be helped is a resident of Northeast Washington who bought her home through the FHA program nine years ago. When her husband, the family's sole source of income, moved out last year, the couple soon defaulted on the mortgage. The woman, the mother of two children, applied for help from HUD, but was rejected. The mortgage company foreclosed.

That woman, who is working now as a school bus driver, is fighting the foreclosure sale in court.

"This is a classic case that fits the criterion of the settlement," said her attorney, Neighborhood Legal Services lawyer Lynn Cunningham.

"The foreclosure occurred through no fault of her own . . . She's gotten a job. She's getting back on her feet. If they reinstated the mortgage, she would be able to pay for it."

The special program to help families who have temporary financial troubles was prompted by a settlement in a 1973 lawsuit filed by legal services lawyers in Chicago. That lawsuit was filed on behalf of a Chicago woman, the mother of seven children, whose lender foreclosed on her FHA-insured house after she missed three payments while hospitalized.

The legal services programs responsible for both suits are supported by the Legal Services Corp., a private nonprofit organization set up by Congress to provide legal aid to the poor civil cases.

Julius M. Williams, director of single-family loan servicing for HUD, said that during the same period between 1976 and this January, about 20,000 families with FHA-insured mortgages received some assistance through the mortgage program and were saved from foreclosure.

But he conceded that some of the allegations about problems with the program were substantiated by a review of some of HUD's ofices. "It (the program) didn't work quite as well as we anticipated, but we're correcting the deficiencies," Williams said.

HUD relies on a list of criteria to determine whether foreclosure should be delayed. For example, if it can be proved that default occurred for reasons beyond the family's control and the family can reasonably be expected to resume payments regularly after a temporary lapse, then that family could avoid foreclosure.

Under, the new settlement agreement, approved Nov. 8 by U.S. District Judge Hubert Will in Chicago, if a former homeowner is found to have been improperly rejected by HUD; he can either get his old home back, or, if it has been resold, he will be supplied with another home from the HUD inventory of foreclosed houses. Further details are being worked out, a HUD spokesman said.

A HUD official said 27,000 leters have been mailed to persons who may qualify for reconsideration of their foreclosure case. Former homeowners who think they may qualify for review must get in touch with their nearest HUD office by Dec. 18 to request reconsideration.