Several dozen vacant and rundown houses and apartments in Washington are to be renovated and rented to low and moderate-income families through the combined efforts of the city and federal governments, local financial institutions and H. R. Crawford, a local property manager and housing consultant.

The new program is an attempt to provide poorer families, who are being squeezed out of many inner city neighborhoods that are being rehabilitated by young, upper income professionals, an opportunity to find affordable housing to rent.

Most of the 62 housing units involved are single-family homes scattered throughout the Shaw neighborhood. Crawford, who bought the houses with financing from local banks and savings and loan associations, will renovate them with $1.3 million in rehabilitation loans from the D.C. government. He will then rent them to families who qualify for a federal rent subsidy program that enables tenants to pay no more than one-fourth of their incomes for rent.

The difference between the amount of rent the tenants can afford and the market rate rents charged by Crawford will be paid by HUD. The units will range from efficiencies to five bedrooms.

The program was announced and praised yesterday afternoon by D.C. Mayor Walter Washington at a press conference at the District Building. The mayor was flanked by representatives of participating banks, savings and loans, the D.C. Department of Housing and Community Development, HUD, the United Planning Organization, the D.C. Chamber of Commerce, local churches, architects, contractors and others.

Crawford, who worked in property management here for a number of years, characterized his project as an "innovative program to serve those who otherwise couldn't afford to do it." It came about, he added, because of the "concern and trust and faith that the financial institutions had in it, and the hard work of others."

Construction is to begin Friday and the project is to be completed within 20 months, according to a press release. Under federal requirements for the rent subsidy program, tenants who qualify for the units will have incomes ranging from $12,600 a year or less for single person to $22,500 a year or less for a family of eight.

Crawford said the average cost of rehabilitation for the single-family houses probably will be about $30,000 or $35,000, with the average cost of renovating apartment units somewhere between $10,000 and $16,000.

In response to questions, Crawford said that he paid an average of $26,500 for the houses, and that he has been offered as much as $35,000 and $40,000 for the dilapidated homes already. He said he expects that when rehabilitation is complete, the homes will be worth anywhere from $75,000 to $85,000 each.

The program, he conceded, allows the corporation he heads to make a "sizable amount" of money.

"I'm not altruistic," Crawford said in response to a question. "While I wanted to help, I also wanted to make some money. And my feeling was that some of those of us in the community who have been successful have to come up with innovative ways to take care of those who otherwise would not be able to afford housing.So my feeling was that perhaps I should invest some of the money I made in this city back into the city, and I certainly hope that others will take heed and do the same thing."

Crawford signed an agreement with HUD yesterday that provides the rent subsidies in a 20-year arrangement that he has the option to renew each five years. Crawford told a reporter that means he can sell the houses after five years if he wants to. But he said he plans to keep them as rental housing if possible. If they are sold, he insisted, they will be sold to "people of modest means."

The renovation loan from the District government - the largest to date under the city's rehabilitation loan program - comes from federal community development block grant funds. It is a 20-year loan at 3 percent interest.

The mayor said yesterday that the rehabilitation housing will add to the several thousand housing units the city has built, has under construction, or plans to construct to assist low and moderate-income families.

Permanent financing for the Crawford's project, about $1.2 million, comes from First Federal Savings and Loan Association, Home Federal Savings and Loan Association, the Industrial Bank of Washington and Perpetual Federal Savings and Loan Association. The Riggs National Bank is to help with rehabilitation costs.

The architect is Bryant and Bryant, a local minority firm, and the contractor is Interstate Contractors and Construction Co. Crawford said the D.C. Chamber of Commerce will help provide some minority contractors to do some of the work.

Crawford, a Democrat who grew up in Washington, was appointed assistant HUD secretary for property management by President Nixon in 1973. He was forced to resign by President Ford in 1976 amid allegations of wrongdoing. But the Justice Department closed its books on his case more than a year ago without finding cause for prosecution.

Crawford is considering running for a D.C. City Council at-large seat this year, but he refused to be specific about his political plans yesterday. "I'm sure that at some time that question will be addressed," he said.