Congress granted authority to the District of Columbia yesterday to sell up to $100 million in bonds next fall to finance housing for lower-income residents.

The measure, enacted by unanimous voice vote in the House and sent to President Carter for his signature, would allow a new D.C. Housing Finance Agency to administer a permanent revolving fund designed to provide construction financing and mortgage funds at interest rates well below the open market.

D.C. Housing Director Robert L. Moore said that rates as low as 9 1/2 to 10 percent could be provided, compared with conventional private mortgages now ranging up to 17 percent.

With as many as 5,000 housing units in planning stages, Moore said he expects the new agency will offer $75 million to $100 million in revenue bonds for sale late this year. The money will be loaned to builders and homebuyers and then repaid over a period of years, permitting the bonds to be paid off. It is expected that more of these so-called revenue bonds will be sold each year to keep the housing program operating.

The bond sale this fall will be the first time a District government agency has directly offered its bonds on the open market.

The measure was passed by the Senate last month.

The city has legal power to finance public improvements with bonds that are to be repaid from future tax collections. However, the city's books were in such disarray when the home rule government took over in 1975 that use of the borrowing authority was delayed by Congress and the city continued to borrow from the U.S. Treasury. City officials hope, after an audit, to shift to the public bond market next year.

The new housing finance agency was created by the City Council in 1978, but remained inactive because it lacked the power granted yesterday to float its own revenue bonds.

The congressional grant of that power comes at a dismal time in the national bond market. Investors, able to get a higher return on other types of investments, have spurned bond purchases, dropping the bottom out of the market.

Moore said the bond market "right now is very bad, but we expect in October or November for it to get fairly good, with interest rates to come down."

In creating the new housing agency, the District will join at least 39 states -- including Maryland and Virginia -- that sell bonds on the private market to finance housing for people unable to qualify at full market rates.

A city-sponsored study committee found last year that nearly 4,000 dwellings for lower-income people must be produced annually until 1985 to meet projected housing demands in Washington.

The money raised by selling the bonds would be used to make loans to build or rehabilitate home units for sale or lease, including apartments, townhouses, condominiums and cooperatives. At least 51 percent of the units in each project must be for low or moderate income families, Moore said.

The housing agency would be permitted to make loans directly to developers or to provide mortgage funds through banks and other private lenders.

The bonds are to be retired and other costs of agency operation are to be met as the borrowers repay loans over a period of years. Under the legislation, the bonds, will not be regarded as municipal debt and their repayment will not be guaranteed by either the D.C. or U.S. governments.

Moore said the agency will be governed by a nine-member board to be nominated by the mayor and confirmed by the City Council. "We will start looking next week at the possible board membership," Moore said.

While legally independant, Moore said the agency will be expected to reflect city housing policies.

The legislation passed by the City Council does not set any limit on the dollar volume of bonds the agency may sell. However, national legislation, which has passed the House and is awaiting Senate action, would set limits.

It would permit the District agency to sell bonds to finance at least $50 million annually and, beyond that, up to 5 percent of all mortgages in this city. "We're looking to see what that will mean," Moore said.