The following story comes from reporter Lauren Hepler, a student at UC Berkeley's School of Journalism.

San Francisco planners see potential to riff on the city’s iconic shared townhouses as part of a new quest to provide more housing options for families from the Mission to the Sunset, who are feeling the strain of rising costs and tight inventory.

Among the proposals in a forthcoming Planning Department whitepaper on housing for families with children is one that aims to encourage a new crop of mid-sized residential developments—like townhouses. In addition, it calls for easing permitting for home additions or in-law units and reevaluating density caps to expand supply.

The proposals in the report, set to be officially released in September, were previewed on Tuesday at a forum hosted by SoMa-based development think tank SPUR.

“One of the startling facts is we have over 700 families living in studios right now in very overcrowded situations,” Sue Exline, a senior planner for the City and County of San Francisco, told several dozen attendees at the forum. “It often comes down to affordability and the size of the unit.”

The proposals reflect a widening effort to hold on to the ever-dwindling number of families in San Francisco, which already claims the nation’s lowest proportion of households with children—18 percent. That number compares to 24 percent in Portland or 30 percent in New York City, according to 2014 Census data.

A small handful of neighborhoods currently house the majority of the city’s families: almost 12,000 kids live in the Mission, Outer Mission and Excelsior, over 7,000 live in the Sunset, and around 4,400 children live in Bayview, according to data provided by Exline.

Whether those areas will adapt or families will be forced to look elsewhere is a question complicated by land limitations and evolving patterns of development.

Several of the neighborhoods the city has identified for housing growth opportunities, such as SoMa, currently house relatively few families. New units coming online in Mid-Market, Mission Bay and elsewhere tend to be high-rise, and outfitted with amenities targeting millennials.

“People often say it costs more to build a three-bedroom unit,” Exline said. “Opportunity lots are small, but they are there.”

The irony for Daniel Parolek, principal of Berkeley-based Opticos Design, is that several neighborhoods, many of them home to large concentrations of families today, provide plenty of historic examples of duplexes, fourplexes or multi-unit structures situated around a central courtyard. He calls this category of housing a “missing middle” between apartment towers and single-family homes.

“I’m not saying we don’t also need larger buildings,” Parolek said. “Cities need to think more about the broad range of housing choices.”

Feeling the Crunch

Rising housing costs are already hitting some families harder than others. The number of black and Asian children in San Francisco, along with middle class households earning $50,000-100,000, all dropped roughly 5 percent from 2000-2014, according to the new report.

No single agency tracks residents’ reasons for leaving the city, making detailed displacement data hard to come by.

Advocacy groups, including the housing-focused nonprofit Causa Justa, have collected anecdotal evidence suggesting price and space are major factors in the exodus of families from San Francisco. Causa Justa, for example, reported one recent case where 10 tenants faced eviction from a $2,850-a-month house in the Mission, after a landlord quietly allowed the home to fall into foreclosure.

Affordability isn't the only important requirement, Exline said. “There is a long list of things families need to stay in a city,” including services like childcare, quality schools and healthy environments.

For new multifamily housing developments outlined in the report, she said walkability or proximity to transit, access to nature or communal space and structural qualities like daylight and good ventilation should be prioritized.

Still, the economic gulf between that vision and today’s reality is vast, the panelists said.

Just 9 percent of homes for sale in San Francisco last year were affordable and big enough to house families earning the area’s median $78,378 income, the report notes. For renters, the National Low-Income Housing Coalition calculates that it takes an annual income of $91,560 to afford the average two-bedroom apartment—about 135 hours of work per week for those making the city’s $13-an- hour minimum wage.

How far subsidies or creative affordable housing models can go will likely be one key question, given that families will still face stiff competition for housing.

“We don’t want command and control over how households are structured, but you might well end up with three 26-year-olds instead of a family with two kids,” said Doug Shoemaker, SPUR board member and president of nonprofit affordable housing developer Mercy Housing. “Most families can’t compete with a three-income household.”