Escalating office rents are forcing the District government to take the boards off some of its vacant school buildings and convert them into offices for city agencies.

With rents for commercial office space hitting $25 a square foot, the city is starting to see the schools, which have remained vacant for years, as a valuable resource, said William Green, who is responsible for managing the school properties.

"We lease 3 million square feet of space around the city," Green said. "As long as rents were low, nobody paid too much attention. Now rents are skyrocketing, and we've got leases expiring."

As a result:

*Grimke Elementary, Vermont Avenue and T Street NW, now houses the fire department's administrative offices.

Bundy School, 429 O St. NW, is being converted into offices for the Mental Retardation and Developmental Disabilities Administration of the Department of Human Services.

*The Lenox Annex, Fourth and M streets SE, is becoming office space for the Department of Public Works.

*Morgan School, 17th & Euclid streets NW, long coveted by various community groups, will be turned into office space for the city next year, Green said.

These schools are among 22 vacant ones that education officials transferred to the city government between 1977 and 1978. The city has already disposed of 14 other schools, for uses ranging from shelters for the homeless to private offices and apartments.

Four other schools buildings remain boarded-up eyesores while city officials weigh their fate. But the school board has recently decided not to transfer any more vacant structures to the city government.

The board contends that city bureaucrats have taken too long to find new uses for the buildings, while irate citizens blame school officials when the vacant buildings become trash collectors. Instead, the board received the authority from the City Council to rent out the space itself.

"If the city had no use for the buildings, they turned into eyesores," said Andrew Weeks, chief of the school system's Division of Buildings and Grounds. "Everyone who drove by got an image not of the city, but of the Board of Education. The board decided it wouldn't have the negative feedback if it leased its own buildings," he added.

Only four of the mostly turn-of-the-century schools are still vacant. They are Mott Elementary, Fourth and W streets NW, and nearby Gage Elementary, Second and Elm streets NW; Crummell Elementary, 16th and Gallaudet streets NE; Carberry, Fifth and D streets NE and the "demountables" or temporary buildings at 16th and Butler streets SE, at the edge of Fort Stanton Park in Anacostia.

The Office of Business and Economic Development controls Crummell, which is zoned for light industrial uses such as warehousing. Half a dozen companies have expressed interest in using that building, and a tenant should be chosen by the end of year, said Kwasi Holman, director of the economic development office.

Gage and Carberry were assigned to the Department of Housing and Community Development eight years ago. This year, DHCD offered to sell Gage and Carberry to private developers for conversion to housing units. Carberry has been tentatively awarded to a developer who plans to turn the building into 25 condominium apartments, said former city housing director James E. Clay.

Only one organization, the Peoples Involvement Corp., submitted a proposal to buy Gage, but its bid was rejected and DHCD has withdrawn the property from the market, Clay said.

The city is attempting to arrange to sell Mott to Howard University, Green said.

The temporary buildings at 16th and Butler streets SE are supposed to be torn down by the city, but a community group recently expressed interest in them and the city is considering that request, Green said.

Even when the city manages to sell a vacant school building, developing it can be a slow process. In 1981, Africare, a nonprofit organization sponsoring development and relief projects in Africa, bought the Morse School at Fourth and R streets NW for its international headquarters.

Today, the building remains boarded up as Africare tries to raise the $1.3 million necessary to renovate the property. The organization has amassed half the money and expects to raise the rest in the next six months, according to Joseph C. Kennedy, director of international development. "Give us another nine months and go by there. Then you should see something," Kennedy said.

Some schools have been converted into imaginative uses by private owners. The Eckington Elementary School, 1615 First St. NE, has become a a four-unit loft apartment building after three local artists bought it in 1981, and the old Shaw Junior High School, Seventh Street and Rhode Island Avenue NW, is now a 145-unit apartment building for the elderly and the handicapped.