San Francisco residents will be getting thousands of new neighbors in the next 30 years, and it's time to start figuring out where they will live and work.

Between 2010 and 2040, the city will need 92,410 new housing units and 191,000 more jobs, said city Planning Director John Rahaim, numbers well above San Francisco's current growth rate.

Combined with the Association of Bay Area Governments' estimate that San Francisco's population will soar from the current 812,000 to at least 964,000 by 2035, it's clear that great change is ahead for the city.

"This (growth) is going to happen whether we plan for it or not," Rahaim recently told the Planning Commission. "The issue is where that development happens."

San Francisco, like other cities, is planning for its future as part of the 2008 state law requiring communities to develop plans that link prospective growth to improved transportation and greenhouse gas reduction.

The Association of Bay Area Governments, which is putting together the "One Bay Area" plan for the region's nine counties and 101 towns and cities, has projected that by 2040 the Bay Area will need 1.1 million more jobs and 660,000 new housing units to accommodate the additional 2.1 million people who will move into the area.

What's the best way?

For San Francisco, handling its share of that growth will require hard choices - and plenty of discussion - about what's best for the city, its residents and its businesses. The city's small size and existing development pattern make the job even tougher, Rahaim said.

Of the 19 major development projects already moving ahead in the city, only two, Balboa Park Station and Parkmerced, are in the western part of San Francisco.

"There's 20 percent of the city where 80 percent of the growth is happening," Rahaim said, and that's unlikely to change in future years.

Some of the biggest development sites already are set. The huge Hunters Point Shipyard project approved in 2010 is slated to include 10,500 housing units and provide 10,000 new jobs. Treasure Island will have 7,000 condos and apartments while the Transbay Center now under construction at First and Mission streets calls for high-rises with 4,500 homes and providing as many as 25,000 jobs.

Other projects are more nebulous. While plans for the Central Corridor - generally bounded by Market, Second, Townsend and Sixth streets - call for adding 8,500 housing units and 34,000 jobs by 2040, few of the project details are concrete.

Coming up short

Even if all the major proposed projects turn out exactly as advertised, which seldom happens when the economics of development are involved, San Francisco will still be about 20,000 homes and 50,000 jobs short of what ABAG projects as the city's share of the Bay Area's growth.

For the city to meet these goals, the focus must be on increasingly dense development south of Market Street, a transit-rich area where much of San Francisco's dwindling supply of buildable land is located.

"There's going to have to be more density," said Tomiquia Moss, community planning director for the San Francisco Planning and Urban Research Association, a local good-government organization. "The Central Corridor can absorb most or all of the projected job growth."

But adding the amount of high-rise construction needed to house a new wave of workers could destroy the community feeling that has brought so many people, workers and residents alike, to SoMa in the first place, especially if those anticipated workers never show up, said John Elberling, president of Tenants and Owners Development Corporation, a community development group that owns eight South of Market residential buildings.

"The city has rose-colored glasses on," he said. The city's projected need for new office space "is far too optimistic; it's magical thinking."

They keep coming

But the continuing migration of companies and their workers into San Francisco is a trend that doesn't seem to be slowing, Rahaim said.

"Companies are looking less at suburban campuses," he said. Their workers increasingly want "transit-served urban environments with a variety of options and a high quality of life."

Business development won't be the only source of the city's growing pains. A continuing influx of workers and residents will boost the need for everything from parks and streetlights to buses and sewer lines.

"Is the city physically capable of growing its roads and transit, its infrastructure?" asked Planning Commissioner Kathrin Moore. "What's the ultimate carrying capacity of the city?"

Problem solving

To Rahaim and other city officials, planned, careful development itself will solve many of those problems, with needed fixes to problems caused by new construction and population growth dealt with before those buildings and developments are approved.

"The transit center, for example, adds 11 acres of open space that doesn't exist now," Rahaim said.

Not all growth-related problems have simple solutions. San Francisco in 2040 will be a much more crowded city than it is today, with the inevitable concerns and troubles that will bring.

Wishing won't make that future go away, said Commissioner Gwyneth Borden.

"Whether we like it or not, we can't stop people from moving to San Francisco," Borden said. "So we have to plan for it."