How many quotes should I get for an ADU job in San Francisco?

At least three. In the permit record the middle half of San Francisco ADU firms usually file between $28,364 and $224,488 a job, so two ordinary firms can sit 7.9 times apart and both be normal for San Francisco. A third quote shows which one is the outlier. Filed values are what contractors wrote on permits, not quotes, so use them to judge the spread, not to price your own job.

What range is normal for ADU jobs in San Francisco?

Half of permits were filed between $73,700 and $275,000; 8 in 10 between $25,600 and $568,000. These are approximate, pooled from each firm's own spread.

Why do prices I see online differ from $169,365?

$169,365 is the construction value contractors wrote on San Francisco permits. Online figures are usually all-in ranges whose scope you can't check (design, fees, site work), and our file mixes small and large jobs of this type in one number. Use the spread above to see where a quote sits.

Do bigger houses get bigger bills?

In the file, yes for the firms: those working on the upper third of homes by value usually file $193,813, the lower third $166,040. That is firms, not single jobs.

Cost to Build an ADU in San Francisco, CA: Usual $169,365 (2026)

How much does it cost to build an ADU in San Francisco?

The usual ADU job filed with San Francisco is $169,365, from 324 priced permits, October 2023 through September 2026. The middle half of firms usually file between $28,364 and $224,488. Half of jobs were filed for less, half for more. A filed value is what the contractor wrote on the permit, not a quote or the final bill. An ADU permit here usually takes 567 days from issue to final inspection. How long permits take →

What the spread looks like

Approximately, from each firm's own spread: every firm's range of filed values, weighted by its 324 priced permits across 267 firms, pooled into one. Half of San Francisco ADU permits were filed between $73,700 and $275,000.

Percentile	Filed value	Reads as
10th	$25,600	1 in 10 permits filed below
25th	$73,700	1 in 4 filed below
50th	$175,000	the middle permit
75th	$275,000	1 in 4 filed above
90th	$568,000	1 in 10 filed above

By home value

Firms split into thirds by the usual value of the homes they work on, with each third's usual filed value weighted by permits. Home values: San Francisco Assessor-Recorder 2025 assessed values (Proposition 13 values, which usually sit well below market value). Under Proposition 13 a home assessed at its 1980s purchase price can carry a value far below what it would sell for today, so treat the home-value matching and the price-versus-similar-jobs comparison as rough.

Firms working on	Usual home value	Usual filed value	Firms	Permits
Lower third	under $799,055	$166,040	88	105
Middle third	$799,055–$1,569,837	$178,346	88	114
Upper third	$1,583,643 and up	$193,813	88	107

Busiest firms and what they usually charge

Top 10 by permits in the last 12 months. Usual is each firm's middle filed value; middle half is the range its middle half of jobs were filed in; both are shown for firms with 5 or more priced permits. Busy is not the same as careful: pick what you value to build a list.

Firm	Permits	Last 12 mo	Usual
R Group, Inc	4	4	—
O Donoghue Construction Inc	3	3	—
Ket Construction Inc	2	2	—
7 Hills Construction	2	2	—
Kyin Way Ngoon	2	2	—
Area Development Inc	2	2	—
Thorpe Design Inc	2	2	—
Huey Const Mngmt Co Inc - dba M H Const	2	2	—
Matarozzi/Pelsinger Builders Inc	2	2	—
Bradford Construction	2	2	—

Why filed values run low or high

Firms working on the most expensive third of homes (usual home value $1,583,643 and up) usually file $193,813, against $166,040 for the least expensive third.
One permit type covers small and large jobs: 1 in 10 ADU permits is filed under $25,600 and 1 in 10 over $568,000, 22 times as much.
97.3% of the 333 permits carry a value; the 9 without one are left out of every figure here.

Is your quote normal? Compare it with 324 filed values

Line your quote up against the file. In San Francisco, 1 in 10 ADU filed values sit under $25,600, the middle half between $73,700 and $275,000, and 1 in 10 over $568,000.

$739,000Above $568,000: higher than 9 in 10 filed values for this work in San Francisco.
$169,365Right at the usual $169,365: in the middle of the file.
$17,900Below $25,600: lower than 9 in 10. Ask what the quote leaves out.

When to schedule ADU construction in San Francisco

San Francisco files the fewest ADU permits in July (79 against an average month of 100) and the most in October (130). If you can choose, ask for quotes in a quiet month. We have no prices by month, so this is about crews' schedules, not a discount. When each trade is busiest in San Francisco →

How these numbers are made

Source: San Francisco DBI building permits on one- and two-family homes, with the contractor from the city's permit contacts file. The window is October 2023 through September 2026; a permit filed after that isn't here yet.

Usual is the middle permit: half were filed for less, half for more. Only permits with a filed value count; a value of $0 or none is left out.

The spread is approximate: we keep seven points of each firm's own range of filed values, not every permit, and pool them.

Nobody paid to be on this page and nobody can. How the records work in San Francisco →

Guides for this trade

All guides →

Common questions

How many quotes should I get for an ADU job in San Francisco?At least three. In the permit record the middle half of San Francisco ADU firms usually file between $28,364 and $224,488 a job, so two ordinary firms can sit 7.9 times apart and both be normal for San Francisco. A third quote shows which one is the outlier. Filed values are what contractors wrote on permits, not quotes, so use them to judge the spread, not to price your own job.
What range is normal for ADU jobs in San Francisco?Half of permits were filed between $73,700 and $275,000; 8 in 10 between $25,600 and $568,000. These are approximate, pooled from each firm's own spread.
How much do ADU builders charge in San Francisco?The usual ADU job is filed at $169,365; the middle half of firms usually file between $28,364 and $224,488. See every firm's usual job →
Why do prices I see online differ from $169,365?$169,365 is the construction value contractors wrote on San Francisco permits. Online figures are usually all-in ranges whose scope you can't check (design, fees, site work), and our file mixes small and large jobs of this type in one number. Use the spread above to see where a quote sits.
Do bigger houses get bigger bills?In the file, yes for the firms: those working on the upper third of homes by value usually file $193,813, the lower third $166,040. That is firms, not single jobs.
Where does this data come from?San Francisco DBI building permits on one- and two-family homes, with the contractor from the city's permit contacts file, read October 2026. How the records work in San Francisco →

Build your list of San Francisco ADU firms →San Francisco permit statistics →How long permits take in San Francisco →ADU vs home addition: what the permit file shows →

ADU cost in other cities: Nashville Raleigh Denver San Diego Honolulu Palo Alto Bellingham Anaheim Marin County (unincorporated) Sacramento County (unincorporated)

Other job costs in San Francisco: Roofing · Kitchen, Bath & Remodel · Windows & Skylights · Decks, Stairs & Porches · Siding, Dry Rot & Exterior Repair · Foundation & Seismic · Addition · Fire Sprinklers & Alarms · Solar & Battery

Cost to Build an ADU in San Francisco, CA: what the permits say