Columbia is a child among Washington area suburbs, barely more than 30 years old. It is the largest and best-known community in a central Maryland county that seemingly has a vast supply of farmland to turn into subdivisions and office buildings.

But planners in Howard County say that they'll run out of developable land in the not-so-distant future and that their bustling bedroom community between Washington and Baltimore needs to turn its attention to revitalizing its aging neighborhoods.

That's strange talk for a place so relatively young, but the concept has proven popular with politicians, civic activists and even the development community as leaders prepare to update their 20-year General Plan, a blueprint for the county's growth.

"Community preservation, I think, will be the major focus of this General Plan," said Joseph W. Rutter, Howard's planning and zoning director.

How the county can achieve that goal will be the chief focus of debate in the weeks to come. Many community leaders say now is the time to address concerns about crime, struggling businesses and poorly maintained neighborhoods. But developers note that the county also should be careful about how it uses its remaining developable land.

"Be sure that it takes advantage of and doesn't waste those assets," said Richard Talkin, a land-use lawyer, referring to a few key parcels in the eastern third of the county.

"I think we need to look at ways that will enable those people who own property in the areas to be revitalized to have incentives to do it . . . in a comprehensive way," Talkin said.

The County Council will spend the next several months addressing how to amend the 1990 General Plan, which in 1991 won a major national planning award. It created distinct boundaries for development, directing most to the eastern third of the county, which includes Columbia and Ellicott City.

Farmland and subdivisions of homes on one-, two- and three-acre lots dominate the landscape in the west, where there is no public water and sewer service.

County Executive James N. Robey (D) has said he would not open up the western part of Howard to more development, and county leaders are expected to keep the basic structure of the plan intact.

Instead, most of their energy will likely focus on taking a plan that had been preoccupied with slowing the rate of growth and adjusting it to place emphasis on sustaining existing communities, Rutter said.

If the county keeps up its current pace of adding about 2,000 residential units a year, it would run out of room for new housing by 2015 given the land-use rules now in place, Rutter said.

There's land for commercial development to continue beyond that, and county officials say the Route 1 and Route 40 corridors are ripe for redevelopment, each with stretches of run-down or vacant storefronts and businesses.

County Council member Mary C. Lorsung (D-Columbia), who started a revitalization committee in 1995 to tackle problems such as broken sidewalks and timeworn buildings, wants to make sure the new General Plan sets out to improve downtown Columbia.

"If we don't at least get a dialogue started, then 10 years from now we won't have anything left to talk about," she said at a council work session last week.

"I think it's a smart approach," Greg Fries, president of the Southern Howard Land Use Committee, said of the talk about revitalization. "If the oldest thing we have is 10 years old and it needs revitalizing, then I think that's the way to go. We should spend on areas that already have existing infrastructure."

Fries said preservation of the rural character of western Howard County should remain a priority of the General Plan. The county has purchased preservation easements on about 18,000 acres of farmland in the western part of the county--preventing them from being developed. The 1990 General Plan set a goal of preserving 30,000 acres.

Fries is one of scores of residents fighting a proposed mixed-use development in Fulton that would add nearly 1,200 housing units and 1.2 million square feet of commercial space on about 500 acres of land that is now a turkey farm in southeastern Howard County. The coalition of homeowners associations that he heads also is fighting in court the county's approval of a Rouse Co. project that would allow almost an identical amount of housing and commercial space on 522 acres just north of the Prince George's County line.

Stewart J. Greenebaum, president of Greenebaum and Rose Associates, the company that wants to develop the Fulton property, said the new General Plan should focus on ways to concentrate expected growth into designated areas instead of spreading it out across the county.

"Zoning regulations, as currently in existence all over the country, actually force sprawl," Greenebaum said. "What has happened is it's politically difficult to foster mixed-use development in a county like Howard County, which is running out of land, because wherever it's suggested, there's going to be an organized group that says 'not in my back yard.' "

Robey appointed a 32-member task force this year to come up with guidelines for updating the General Plan. Council members adopted some ground rules last night.

Joyce Kelly, former president of the Howard County Citizens Association and a member of the General Plan task force, said the county should focus on environmental concerns, the need for more housing for senior citizens, and revitalization of existing communities. "If you just did those three things, you'd make remarkable progress in this county," she said.

Kelly, a resident of western Howard County since 1972, said that as the county moves closer to build-out, the General Plan--and the council's ability to adhere to it--becomes more important. "If this council doesn't step up to the plate and make some hard decisions, then you might as well write Howard County off," she said. "The ball's in their court, probably more so than ever."