What is the 2026 cost range for a attached adu scope adu in San Francisco?

$265,050-$559,550, with the median landing near $412,300. The range reflects finish tier and layout complexity within the attached adu scope; the San Francisco labor multiplier of 1.55× vs national median is baked in.

How long does a attached adu scope adu take in San Francisco?

22-32 weeks of on-site construction for the attached adu scope, plus 10-26 weeks of permit review in San Francisco if the scope requires a permit. Cosmetic-only refreshes often skip permits; anything touching plumbing, electrical, or structural does not.

What is the single biggest budget-overrun risk for this scope?

Utility separation surprises — some markets require a new electrical service drop from the street, not just a sub-panel. Utility-company coordination adds 6-10 weeks and $8-14K.

ADU — Attached ADU Cost in San Francisco, 2026

Low

$265K

$265,050

Median

$412K

$412,300

High

$560K

$559,550

Scope timeline: 22-32 weeksSan Francisco permit window: 10-26 weeksUpdated 2026-04-24

Why attached adu × San Francisco produces this band

A attached adu scope for a adu in San Francisco combines two price levers: scope and metro labor rates. Attached ADUs share a wall with the primary house. Needs its own entrance, fire-rated separation, and (in most jurisdictions) independent utility metering — but shares the site's foundation-extension cost. Against the national median remodel labor rate, San Francisco runs 55% above the national median — so the attached adu band comes in 5% below the mid-range, then scales 55% above the national median on top of that. Permit timelines for residential work in San Francisco typically run 10-26 weeks, which is the window you plan your design and decision sequence against. This page gives you the actual 2026 San Francisco bands for this exact combination, plus the three cost drivers Baily asks about first when scoping the project live.

What drives cost for a attached adu scope

·Fire-rated wall assembly (typically 1-hour, sometimes 2-hour)
·Independent utility service drops
·Shared-wall sound isolation (STC 50+)
·Grading and drainage on the new footprint

What makes San Francisco different

Labor — Bay Area CSLB-licensed contractor scarcity keeps labor rates the highest in California.
Labor — Union framing and electrical rates carry a 30-35% premium over national median.
Labor — Tech-sector remodel demand (Noe Valley, Pacific Heights, Sea Cliff) competes for premium-finish crews.
Material — Victorian + Edwardian heritage restoration uses specialty millwork and painters — significant premium.
Material — Title 24 energy code same as rest of CA — envelope + glazing premium.

San Francisco rules that affect this scope

SF DBI permit process is notably long (10-26 weeks typical; discretionary review on most kitchen/bath >$25K).
Section 317 (Residential Demolition) controls ADU and addition work — lot merger and demolition ratio tracked.
Historic Preservation Commission review for Articles 10 + 11 properties adds 8-16 weeks.
Soft-story retrofit ordinance (SF Ordinance 66-13) affects multi-family properties with tuck-under parking.

Scope your adu with Baily.

Baily asks the eight questions that determine where your project lands inside the $265K-$560K band for San Francisco and hands the scoped brief to one licensed builder.

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Questions LA homeowners actually ask

$265,050-$559,550, with the median landing near $412,300. The range reflects finish tier and layout complexity within the attached adu scope; the San Francisco labor multiplier of 1.55× vs national median is baked in.