Permits through August 2026Yearly permits since 1995San Mateo County index 1975–2025
San Mateo County (100 = first year)United States, rebased to the same startNBER recession
House prices are indexed by county, not by city: this is San Mateo County's FHFA index, with the national index rebased to the same start.
Census Bureau notes: building permit figures cover new privately owned housing units authorised by permit-issuing places; permits do not mean the units were started or completed, and places that report less often than monthly are imputed in monthly totals. FHFA notes: The FHFA HPI is a broad measure of the movement of single-family house prices. The FHFA HPI is a weighted, repeat-sales index, meaning that it measures average price changes in repeat sales or refinancings on the same properties.
South San Francisco, California (San Mateo County), authorised 34 housing units through building permits in the 12 months to August 2026, −94.2% on the previous 12 months.
34 of those units were single-family houses (100%), 0 were in two- to four-unit buildings and 0 in buildings of five or more units. That is 0.5 units per 1,000 residents, well below the county's 2.2 and well below the state's 2.8.
Since 1995 the place has authorised 4,058 units, with the busiest year 2025 (585 units). San Mateo County's FHFA house price index rose +49.1% over the ten years to 2025.
34units permitted, 12 months to August 2026−94.2% on the previous 12 months
34single-family units100% of the total
0units in 5+ unit buildings0% of the total
0.5units per 1,000 residentsSan Mateo County 2.2 · California 2.8
Permits by month and structure type
Housing units authorised in South San Francisco by month, latest 24 monthssingle-family2+ unit buildings
Units, 12 months to August 2026
South San Francisco
San Mateo County
California
United States
All housing units
34
1,600
111,538
1,418,086
Single-family (1 unit)
34 (100%)
468 (29%)
55,792 (50%)
888,241 (63%)
2 units
0
38
4,172
34,814
3–4 units
0
9
1,193
17,298
5 or more units
0 (0%)
1,085 (68%)
50,381 (45%)
477,733 (34%)
Units per 1,000 residents
0.5
2.2
2.8
4.1
Change on previous 12 months
−94.2%
−15.7%
+13.8%
−0.1%
Permits by year since 1995
Housing units authorised in South San Francisco by year, 1995–2025single-family2+ unit buildings
4,058 units since 1995; the busiest year was 2025. Annual figures include units imputed for months a place did not report.
Home prices in San Mateo County
FHFA's index for San Mateo County rose +49.1% over the ten years to 2025 (+4.1% a year) and −0.6% in the latest year, against +80.3% and +0.8% for California. Full county page: decade table, peak-to-low declines, every ZIP code and every permit-issuing place in the county.
Questions and answers
How many homes are being built in South San Francisco, CA?
34 housing units were authorised by building permits in the 12 months to August 2026, against 588 in the previous 12 months.
What kind of housing is being permitted in South San Francisco?
34 single-family units, 0 in two-unit buildings, 0 in three- and four-unit buildings and 0 in buildings of five or more units.
How does South San Francisco compare with its county and state?
0.5 units per 1,000 residents in South San Francisco, 2.2 in San Mateo County and 2.8 in California.
How have home prices moved in San Mateo County?
FHFA's index for San Mateo County rose +49.1% over the ten years to 2025 and −0.6% in the latest year; the county page has the full series.
What does a permit count?
A housing unit authorised by a building permit for new privately owned residential construction, as reported to the Census Bureau Building Permits Survey by the permit-issuing office. Permits are not completions; some permitted units are never built, and places that report only annually are imputed in monthly figures.
Provenance
Permits: US Census Bureau, Building Permits Survey, place-level monthly and annual files through August 2026 (permit office 448000); county and state comparisons from the county and state files. Population: Census Bureau vintage 2025 estimates for incorporated places, matched on FIPS place code where the permit office is one. House price index: Federal Housing Finance Agency. Public domain. Corrections · Building Permits Survey.