Negotiations between Capitol Hill residents and a local developer have saved three 19th Century houses that had been slated for demolition.

The houses are among six that were to be razed to make way for a townhouse-condominium complex on a 1-acre site at 3rd Street and Maryland Acenue, 2 1/2 blocks northeast of the Capitol. Barrett Linde, of Management and Development Associates, Inc., the firm planning the complex, said that "it will probably not be feasible" to save the other three houses. The buildings that will be preserved are at 238 Maryland Ave. and 212 and 214 3rd St. NE.

Neigborhood activists hope to preserve at least one or two of the remaining builings.

"The community is not simply dropping this and walking away just because the formal negotiations have ended," said Janet Gordon of Advisory Neighborhood Commission 6B, which helped negotiate for preservation of the houses.

The other two houses that the community is interested in preserving are at 224 and 226 Maryland Ave. Both are Greek Revival structures built in the 1850s. The third house is a small building obscured by vines, which community leaders say they are willing to sacrifice.

Plans to raze the houses began last July when Warren Gardner, who owns one of the houses, and William Thomson, who owns the other five, applied for demolition permits. Since the buildings are in the Capitol Hill Historic District, the applications were referred to the Joint Committee on Landmarks, a federal-District review board.

Upon the recommendation of the Joint Committee, State Historic Preservation Officer Lorenzo Jacobs invoked a 180-day delay in demolition. During the waiting period, which expired March 26, Jacobs conducted five negotiation sessions between the developers and community groups.

As a result of the negotiations, Management and Development Associates, which has a contravt to purchase the property, agreed to preserve the three Victorian, brick rowhouses and to incorporate them into the townhouse complex.

The firm, which originally planned to build 82, one-bedroom units, also agreed to reduce that number to about 70 and, in response to community pressure, is considering larger units suitable for families.

Although architectural plans for the complex have not beeb drawn up, Linde agreed to a community request and will depart from "the Federalist style that had characterized my work to date." The community hopes the complex will be designed to blend with the surounging neighborhood.

In addition, Linde agreed to change the location of the curb cut ' the position of the alley leading to the interior of the projected complex - as requested by volunteer architects Mark McInturff and Milton Shinberg. The two architects worked with a coalition of community groups including the ANC 6B, the Stanton Park Neighborhood Association the Capitol Hill Restoration Society and Don't Tear It Down, Inc.

Bernard Gewirz, president of Management and Development Associates, said the firm hopes to start construction of the project this summer. He called the negotiating process "most enlightening.)

"We changed our plans for the better," he said, "but a delay of six months is extensive and expensive. I would rather see a 90-day delay and more intensive negotiation. That way, inflation could be controlled. As it is, the delay will add considerably to the cost of the project."

Originally, the one-bedroom units were to sell for $55,000. Gewirz said he did bot know what the selling price would be now.

Nancy Taylor, an aide to the Joint Committee, characterized the negotiations as successful.

The District regulation, which allows the 180-day demolition delay and applies to landmark buildings or those within historic districts, has been invoked nine times since it was passed in 1973. In three cases, where demolition permits have been sought, the houses are still standing but in danger of being razed. The Maryland Avenue case is the first one in which a developer has agreed to preserve houses originally slated for demolition, according to sources at the Joint Committee on Landmarks.

Tenants of the Maryland Avenue and 3rd Street houses have been told they have until April 30 to vacate. Community leaders expect they will have a least until then before the three other houses are razed.

So far, two offers have been made by community residents to purchase the hose at 226 Maryland Ave.

"We are pleased with the concessions the developer has made," said Mary W. Jayne, who with her husband, has made one of the purchase offers,

Jayne, who represented the Stanton Park Neighborhood Association in the negotiations, added, "But we want to pursue every possible avenue to saving 226 Maryland Ave., and we hope someone will buy 224 also."