Bay Area owners weighing an ADU in San Francisco (DBI plan-check, RH-1/RH-2 lots, Sunset/Richmond garage conversions) vs Oakland (looser ordinance, EBMUD water drop, Hills WUI). Cost-per-sqft and permit clock are the headline differences.
Head-to-head, 2026 numbers
Metric
San Francisco
Oakland
Detached ADU ($/sqft)
All-in installed, 2026 USD.
$550–$750
$475–$625
Garage conversion ($/sqft)
$325–$475
$275–$400
Ministerial permit clock
End-to-end, including agency back-and-forth.
14–22 wk
10–14 wk
Discretionary review
22–40 wk
18–30 wk
Permit story
San Francisco
San Francisco permits are the slowest in our Bay Area service area, but they're predictable once you pick the right track. State ADU Law gives ministerial approval at 60 days from a complete submittal. The SF Local Program is more flexible (allows unlimited ADUs in some multifamily buildings) but adds Section 311 neighborhood notification and Planning review on top of DBI. The schedule variables are which track you choose, whether exterior changes trigger 311, and the DBI queue.
Oakland runs ADU plan check through its Planning & Building Department and applies state ADU law on top of a local ordinance that streamlines conversions and pre-approved plans. The real schedule variables aren't the building permit itself — they're the EBMUD water service drop, the Wildland-Urban Interface overlay on the Oakland Hills, and the city's soft-story retrofit ordinance on older multifamily buildings.
☐Coastal Zone applies to the Ocean Beach / Sunset / Richmond strip.
☐Rent Ordinance (Chapter 37) caps demolition of pre-1979 units.
Oakland
☐RD-1, RD-2, RM zones — state ADU law applies; one detached ADU + one JADU per single-family lot.
☐S-9 Wildland-Urban Interface overlay on the Hills.
☐Mandatory Soft-Story Retrofit applies to many pre-1991 wood-frame multifamily.
☐Rent-controlled units (pre-1983) trigger Just Cause + relocation rules on demolition.
What pushes cost up or down
San Francisco
·Highest Bay Area construction cost — small lots, narrow streets, parking impossible.
·Hillside / downslope lots (Diamond Heights, Twin Peaks, Bernal Heights east) add $40–150k in retaining and access.
·SFPUC water + sewer connection fees are the highest in the region.
·Soft-story retrofit pairing on a multifamily building can add $80–200k tied to the ADU permit.
Oakland
·Oakland Hills hillside lots add $40–120k in geotech, retaining, and crane access vs flat flatland lots.
·WUI Chapter 7A assemblies (Hills) add $18–35k in exterior materials.
·EBMUD water service upgrade commonly $8–18k when the existing service is undersized.
·Pre-1978 lead paint abatement on retrofit/conversion work runs $5–18k.
The honest verdict
The cheaper detached build, on paper, is Oakland (top-end $625/sqft vs $750/sqft). The faster permit clock belongs to Oakland (14 weeks vs 22 weeks ministerial). Those headlines flip once you factor in overlays, water-utility coordination, and design constraints — which is why we sketch the parcel before we ever quote a number.
Most detached SF ADUs land between $375K and $550K all-in. Garage conversions typically run $200K–$310K. SFPUC connection fees and tight site access push costs above other Bay cities.
State ADU Law or SF Local Program — which track?
State ADU Law is faster (ministerial, no 311 notification) but caps the unit count. SF Local allows more units in qualifying multifamily but adds Section 311 + Planning review. We pick the track during feasibility based on building type and unit goal.
Will my ADU trigger Section 311 neighborhood notification?
On the SF Local Program track, almost always. On State ADU Law track, only if the project includes exterior changes visible from a public right-of-way. We design to stay inside the state track when timeline matters.
How much does an ADU cost in Oakland?
Most detached Oakland ADUs land between $300K and $450K all-in. Garage conversions typically run $165K–$260K. Hillside parcels and WUI fire-zone assemblies can push detached projects above $500K.
Does Oakland have pre-approved ADU plans?
Yes — the city maintains a small library of pre-approved plans that bypass most of architectural plan check. Useful when the lot is flat, the setbacks are clean, and you don't need a custom layout.
Do I need a fire-rated exterior in the Oakland Hills?
If the parcel is inside the Wildland-Urban Interface overlay (most of Montclair, Crocker Highlands, Hiller Highlands), yes — Chapter 7A applies and adds roughly $18–35k in materials over a non-WUI build.