Bedroom counts offer one way to compare the Bay Area’s housing stock, but they tell a different story from home prices. A San Francisco Chronicle analysis of federal data found that the region’s highest average bedroom counts are in suburban communities such as Diablo and Atherton, where homes average more than four bedrooms.
The San Francisco Chronicle analyzed U.S. Census American Community Survey data on bedroom counts across Bay Area ZIP codes with more than 250 homes. Reporter Danielle Echeverria, who covers data for the paper and joined the Chronicle in 2021, found that average bedroom counts tend to be higher farther from San Francisco, particularly in the East Bay and far down the Peninsula.
The Chronicle’s analysis found a relationship between wealthier locations and higher average bedroom counts. Diablo, northeast of Danville, and Atherton both average more than four bedrooms per home. The American Community Survey asks residents how many bedrooms their homes have; that measure is distinct from the number of rooms.
Where the Bay Area’s bedroom counts are highest
The Chronicle found that suburban ZIP codes generally have higher average bedroom counts than San Francisco ZIP codes, with top results concentrated in Contra Costa and Santa Clara counties. Los Altos, Saratoga and Danville, as well as San Jose’s Almaden neighborhood, were among the places with large homes in the analysis.
The analysis also found averages near four bedrooms in ZIP code 94957, covering Ross in Marin County, and 94552, covering Castro Valley in Alameda County. Those bedroom counts describe the housing stock, not the prices residents can afford. The Chronicle framed the findings as a contrast between San Francisco’s AI-era wealth and the larger homes more common outside the city.
San Francisco’s figures depend on the measure
Within San Francisco, ZIP code 94127, west of Twin Peaks, has the city’s highest average bedroom count in the Chronicle’s analysis; it is not the same area as the Pacific Heights or Presidio Heights mansion districts. The article also reports 3.1 rooms per home there, a different measure from bedrooms per home. At the other end of the city, the Tenderloin’s 94102 ZIP code averages less than one bedroom per housing unit. San Francisco County as a whole also averages less than one bedroom per home, the lowest figure among the Bay Area counties cited in the analysis.
At the county level, Contra Costa has the highest average bedroom count in the nine-county Bay Area, at about three bedrooms per home, according to the Chronicle. Solano ranks second. Santa Clara, Alameda, Marin, Napa, Sonoma and San Mateo counties each average roughly 2.5 bedrooms per home.
What the Census data measures
The U.S. Census Bureau makes American Community Survey five-year estimates available for ZIP Code Tabulation Areas, a geography used for ZIP-code-level comparisons. Bedroom counts and rooms per unit are separate measures, so the 3.1-room figure reported for 94127 should not be read as 3.1 bedrooms. For a different view of housing stock, the Census Bureau’s 2023 ACS table B25024 measures units in structure, separate from bedroom counts. That is a distinct measure; the bedroom figures discussed above do not provide a comparison of detached single-family-home shares.
Price and space offer different lenses
The pattern tracks with broader housing trends reported elsewhere. Remote workers pushed into the outer Bay Area in search of extra bedrooms and home offices during the pandemic, driving up home prices in the region's relatively affordable pockets, according to Yahoo Finance. That same reporting notes that single-family home sizes in the Bay Area swelled in the late 1980s, a period that also saw rapid suburban development across the region, though homes built in more recent years have trended somewhat smaller.
Home-value figures provide a separate comparison from bedroom counts. Palo Alto’s 94301 ZIP code had the Bay Area’s highest typical home value per square foot among ZIP codes with at least 5,000 residents in March, topping $2,000 per square foot, with Atherton close behind at more than $1,900, according to Zillow-based figures cited by Yahoo Finance. In ZIP code 94571, covering Rio Vista and nearby Solano County communities, homes cost less than $300 per square foot; at that rate, a $1 million budget could buy roughly 3,600 square feet, far more space than the same budget would buy near Palo Alto.
Yahoo Finance also reported that San Francisco home values fell from about $1,200 per square foot in 2019 to roughly $1,000 after adjusting for inflation. Zillow’s underlying figures cover single-family homes and condominiums and estimate what a mid-tier home in a ZIP code might sell for. That measure does not count bedrooms, but it provides another way to view the differences between Bay Area markets.
