Descriptive Title: Percent of households with 1 person or fewer per habitable room (i.e. not overcrowded)

Geographic Unit of Analysis: Census tract

Percent of households with 1 person or fewer per habitable room (not overcrowded) (2005-2009)
NeighborhoodPercent90% MOE*
Bayview/Hunter's Point 90.9% 1.7%
Bernal Heights 96.7% 2.3%
Castro/Upper Market 99.0% 1.4%
Chinatown 75.6% 2.8%
Excelsior 93.3% 2.2%
Financial District/South Beach 94.3% 1.6%
Glen Park
Golden Gate Park NA NA
Haight Ashbury 99.2% 1.3%
Hayes Valley
Inner Richmond 97.6% 1.1%
Inner Sunset 98.2% 1.4%
Lakeshore 96.4% 1.9%
Lincoln Park
Lone Mountain/USF
Marina 99.0% 0.8%
McLaren Park
Mission 90.3% 1.4%
Mission Bay
Nob Hill 92.8% 1.1%
Noe Valley 99.6% 2.1%
North Beach 94.2% 1.0%
Outer Mission 91.8% 3.4%
Outer Richmond 96.7% 1.6%
Pacific Heights 99.3% 1.2%
Potrero Hill 98.6% 2.7%
Presidio 97.9% 2.0%
Presidio Heights 99.7% 2.5%
Russian Hill 96.8% 1.2%
San Francisco 94.9% 0.2%
Seacliff 98.9% 5.0%
South of Market 91.9% 0.9%
Treasure Island 98.3% 9.1%
Twin Peaks 100.0% 8.6%
Visitacion Valley 86.7% 2.6%
West of Twin Peaks 99.3% 2.4%
Western Addition 98.4% 0.8%
Housing stock by number of bedrooms 2000 2009-2011
Number of Bedrooms Units Percent Units* Percent
Studio 62,278 18% 52,788 14%
One bedroom 96,929 28% 99,026 26%
Two bedrooms 103,199 30% 117,972 31%
Three bedrooms 59,793 17% 72,704 19%
Four or more bedrooms 24,328 7% 34,679 9%
Total 346,527 100% 377,169 100%
* Note that 2009-2011 unit count by bedroom is an estimate. 
Data source:  2000 US Census and 2009-2011 American Community Survey

Why Is This An Indicator Of Health and Sustainability?

The impacts of overcrowding on health are both direct and indirect. Most immediately, crowding increases risks for respiratory infections such as tuberculosis and ear infection.a Overcrowded housing has also been associated with increased mortality rates (particularly for women), meningitis, and Helicobacter pylori bacteria which can cause stomach ailments.b Crowded housing conditions also contribute to poor child development and school performance, in part, because overcrowding limits the space and quiet necessary for children to do homework.c,d Overcrowding may act cumulatively with other environmental health stressors. For example, one recent study found that crowding combined with noise significantly increases chronic stress hormones in low-income children.e Finally, overcrowding affects health indirectly by creating conditions conducive to poor sanitation, high environmental noise, and residential fires.

Interpretation and Geographic Equity Analysis

For this indicator, overcrowding, as defined by the U.S. Department of Housing and Urban Development (HUD), is greater than 1.01 people per habitable room. Severe overcrowding is defined as greater than 1.51 people per habitable room. Because overcrowded units are the minority, estimates of overcrowding from the American Community Survey were statistically unreliable (statistical reliability increases with when the number of people falling into a category increases). Thus, data are presented as the number of units that are NOT overcrowded. Therefore, neighborhoods and census tracts with a LOWER percentage of households that are NOT overcrowded should be interpreted as a poor outcome.

The neighborhoods that have the fewest households living in uncrowded conditions are Chinatown, Visitacion Valley, Downtown/Civic Center, and Oceanview. The situation in Chinatown is particularly bad, with only 76% of households living in uncrowded conditions. The neighborhoods with the most people living in uncrowded households are Twin Peaks, Diamond Heights/Glen Park, Presidio Heights, and Noe Valley. 


Data was obtained from the American Community Survey (ACS). Living rooms, dining rooms, kitchens, bedrooms, finished recreation rooms, enclosed porches suitable for year-round use, and lodger’s rooms are included. Excluded are strip or Pullman kitchens, bathrooms, open porches, balconies, halls or foyers, half rooms, utility rooms, unfinished attics or basements, or other unfinished spaces used for storage. A partially divided room is considered a separate room only if there is a partition from floor to ceiling, but not if the partition consists solely of shelves or cabinets.

The total number of households with 1 person or less per room was divided by the total number of occupied households and the margins of error were recalculated using the ACS users handbook. For more information on the margin of error or ACS guidance, please visit:

The ACS is a sample survey, and thus, data are estimates rather than counts. Estimates have accompanying margins of error that indicate the span of values that the true value could fall within.  Margins of error should be subtracted from and added to the estimate to determine the range of possible values. If the margin of error is too big relative to the value, data are not shown because they are statistically unstable.  A coefficient of variation of 30% was used to determine statistical instability.


HUD notes that renters, lower income households, and foreign-born population living in central cities are more likely to live in overcrowded homes. These populations have been noted to be more frequently missed by the Census, and this this data may overestimate the number of households living in uncrowded homes. 

Data Source

American Community Survey (ACS), 5-year Estimates, 2005-2009.

Map and table created by San Francisco Department of Public Health, Environmental Health Section using ArcGIS software.

Map data is presented at the level of the census tract. The map also includes planning neighborhood names, in the vicinity of their corresponding census tracts.

Table data is presented by planning neighborhood. Planning neighborhoods are larger geographic areas than census tracts. SFDPH chose to use the San Francisco Planning Department's census tract neighborhood assignments to calculate neighborhood values. This assignment method relies on a 'centroids within' methodology to convert census tracts to geographic mean center points. Census tracts are assigned to planning neighborhoods based on the spatial location of those geographic mean center points and neighborhood totals are calculated for the table. In a few cases, certain census tracts were re-designated to different neighborhoods based on knowledge of the population dispersion in the tract.

Detailed information regarding census data, geographic units of analysis, their definitions, and their boundaries can be found at the following links:

Interactive boundaries map

Number of bedrooms from the 2000 US Census and the 2009-2011 American Community Survey. 

  1. Krieger J, Higgens DL. Housing and Health: Time again for Public Health Action. American Journal of Public Health. 2002;92:758-768.
  2. Office of Deputy Prime Minister. 2004. The impacts of overcrowding on health and education: A review of the evidence and literature. London. Last accessed online August 30, 2007 from:
  3. Ross DP, Roberts P. Income and child well being: A new perspective on the policy debate. Canadian Council for Social Development. Ottawa. 1999.
  4. Cooper, Merrill. Housing Affordability: A Childrens Issue. Canadian Policy Research Networks Discussion Paper. Ottawa. 2001
  5. Evans G, Marcynyszyn LA. Environmental Justice, Cumulative Environmental Risk, and Health among Low- and Middle-Income Children in Upstate New York. American Journal of Public Health 2004;94: 1942-1944.