Building an ADU in California

Know your ADU requirements before you build

Pre-Reviewed
Dwell 1178
$
1178
sf
62
'
x
19.0
'
Plan Details →
Pre-Reviewed
Live Plus 741
$
741
sf
38
'
x
19.5
'
Plan Details →
Pre-Reviewed
Live 576
$
576
sf
32
'
x
18.0
'
Plan Details →
Pre-Reviewed
Flex 322
$
322
sf
23
'
x
14.0
'
Plan Details →
Pre-Reviewed
Evan
$
119
sf
14
'
x
8.5
'
Plan Details →
Pre-Reviewed
Evan Plus
$
240
sf
20
'
x
12.0
'
Plan Details →
Pre-Reviewed
Mini Kit
$
120
sf
12
'
x
10.0
'
Plan Details →
Pre-Reviewed
Studio Kit
$
240
sf
24
'
x
10.0
'
Plan Details →
Pre-Reviewed
Tal 468
$
468
sf
26
'
x
18.0
'
Plan Details →
Pre-Reviewed
Aya 720
$
720
sf
30
'
x
24.0
'
Plan Details →
Pre-Reviewed
Adam 1000
$
1000
sf
40
'
x
25.0
'
Plan Details →
Pre-Reviewed
Adam 520
$
520
sf
26
'
x
20.0
'
Plan Details →
Pre-Reviewed
Sela Mini
$
80
sf
10
'
x
8.0
'
Plan Details →
Pre-Reviewed
Alon 240
$
240
sf
20
'
x
12.0
'
Plan Details →
Pre-Reviewed
A-frame 120
$
120
sf
12
'
x
10.0
'
Plan Details →
Pre-Reviewed
Casita 850
$
850
sf
39
'
x
33.0
'
Plan Details →
Pre-Reviewed
The 620
$
620
sf
44.4
'
x
14.0
'
Plan Details →
Pre-Reviewed
The 240
$
240
sf
24
'
x
9.9
'
Plan Details →
Pre-Reviewed
Zion 1280
$
1280
sf
56
'
x
40.0
'
Plan Details →
Pre-Reviewed
Microhaus
$
136
sf
19
'
x
7.2
'
Plan Details →
Pre-Reviewed
Prospect
$0
800
sf
38
'
x
32.1
'
Plan Details →
Pre-Reviewed
Adore Horizon 866
$0
866
sf
31.6
'
x
27.6
'
Plan Details →
Pre-Reviewed
Connect 3
$0
960
sf
40
'
x
24.0
'
Plan Details →
Pre-Reviewed
Arlo
$0
535
sf
42
'
x
12.8
'
Plan Details →
Pre-Reviewed
Snap ADU Two-Story 2b2b
$0
1200
sf
30
'
x
20.0
'
Plan Details →
Pre-Reviewed
The Modal 01
$0
432
sf
32
'
x
13.5
'
Plan Details →
Pre-Reviewed
Napa 600
$
600
sf
30
'
x
20.0
'
Plan Details →
Pre-Reviewed
SOL 480
$
480
sf
24
'
x
20.0
'
Plan Details →
Pre-Reviewed
Navajo 960
$
960
sf
40
'
x
24.0
'
Plan Details →
Pre-Reviewed
Vor 640
$0
640
sf
40
'
x
16.0
'
Plan Details →
Pre-Reviewed
The 146
$0
146
sf
15
'
x
10.0
'
Plan Details →
Pre-Reviewed
The 106
$0
106
sf
11
'
x
10.0
'
Plan Details →
Pre-Reviewed
Novato 1200
$
1200
sf
37.6
'
x
32.0
'
Plan Details →
Pre-Reviewed
Kithaus K6
$0
330
sf
25.5
'
x
13.0
'
Plan Details →
Pre-Reviewed
Kithaus K9
$0
496
sf
38
'
x
13.0
'
Plan Details →
Pre-Reviewed
Kithaus K4
$0
226
sf
17.4
'
x
13.0
'
Plan Details →
Pre-Reviewed
Kithaus K7
$0
390
sf
30
'
x
13.0
'
Plan Details →
Pre-Reviewed
HO4
$0
1280
sf
40
'
x
32.0
'
Plan Details →
Pre-Reviewed
mTwo
$
800
sf
33
'
x
24.0
'
Plan Details →
Pre-Reviewed
HO3
$0
960
sf
40
'
x
24.0
'
Plan Details →
Pre-Reviewed
mOne
$
400
sf
34
'
x
12.0
'
Plan Details →
Pre-Reviewed
Connect 5
$0
1600
sf
40
'
x
40.0
'
Plan Details →
Pre-Reviewed
Connect 2
$0
640
sf
40
'
x
16.0
'
Plan Details →
Pre-Reviewed
Model 480
$0
480
sf
24
'
x
20.0
'
Plan Details →
Pre-Reviewed
Model 264
$0
264
sf
22
'
x
12.0
'
Plan Details →
Pre-Reviewed
Plus Hus Full
$0
320
sf
20
'
x
16.0
'
Plan Details →
Pre-Reviewed
Sela Plus
$0
120
sf
12
'
x
10.0
'
Plan Details →
Pre-Reviewed
Erez 540
$0
540
sf
27.25
'
x
20.0
'
Plan Details →
Pre-Reviewed
Adam 800
$0
800
sf
40
'
x
20.0
'
Plan Details →
Pre-Reviewed
Oren 1104
$0
1104
sf
48
'
x
23.0
'
Plan Details →
Pre-Reviewed
Gal 442
$0
442
sf
30
'
x
14.8
'
Plan Details →
Pre-Reviewed
The H1200a
$0
1200
sf
45
'
x
26.6
'
Plan Details →
Pre-Reviewed
The H750
$0
750
sf
32
'
x
23.0
'
Plan Details →
Pre-Reviewed
The H650b
$0
650
sf
44
'
x
15.0
'
Plan Details →
Pre-Reviewed
The H800
$0
800
sf
40
'
x
20.0
'
Plan Details →
Pre-Reviewed
Duo
$0
481
sf
42
'
x
11.5
'
Plan Details →
Pre-Reviewed
Mono
$0
321
sf
28
'
x
11.5
'
Plan Details →
Pre-Reviewed
Holo
$0
240
sf
24
'
x
10.0
'
Plan Details →
Pre-Reviewed
Abodu Two
$0
610
sf
44
'
x
14.0
'
Plan Details →
Pre-Reviewed
Abodu One
$0
500
sf
35
'
x
14.0
'
Plan Details →
Pre-Reviewed
Abodu Studio
$0
340
sf
28
'
x
12.0
'
Plan Details →
Office
Office
3 Bedroom
3 Bedroom
2 Bedroom
2 Bedroom
2 Bathroom
2 Bathroom
1 Bathroom
1 Bathroom
In Unit Washer / Dryer
In Unit Washer / Dryer
1 Bedroom
1 Bedroom
Studio
Studio

ADUs you can build in California

These are the types of ADUs that you can build on residential properties
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Junior Accessory Dwelling Unit (JADU)
A Junior ADU (JADU) is an ADU of no more than 500 square feet. A JADU must be within a proposed or existing single-family home or accessory structure, such as a garage.

Unlike ADUs, JADUs may share a bathroom with the single-family home and must only meet “efficiency kitchen” requirements.
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Accessory Dwelling Unit (attached / detached)
Detached ADUs are located in free-standing buildings that are separate from the main single-family home or multi-family building.

Attached ADUs involve adding on to a single-family home.

ADUs are typically no more than 1,200 square feet.
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Conversion ADUs
Conversions are constructed by converting part of an existing single-family or multi-family home, or by converting all or part of an accessory building (like a garage, shed, or studio). This includes garage conversions.
Icon with the letter "I" in a circle that signifies more information
Tiny Home on Wheels (THOW)
Description coming soon
Icon with the letter "I" in a circle that signifies more information
Duplex / Triplex
Description coming soon

The ADU rules

Know what's allowed before you build an ADU

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Setbacks

Detached ADUs are located in free-standing buildings that are separate from the main single-family home or multi-family building.

Attached ADUs involve adding on to a single-family home.

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Square Footage

The max size of an ADU is determined by the size of the primary dwelling on the property. For single-family homes, the max allowable size for an attached ADU is 50% of the existing living area of the primary dwelling, up to a maximum of 1,200 square feet. For detached ADUs, the maximum size is 1,200 square feet regardless of the size of the primary dwelling.

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Height

Generally, you should be able to build an ADU that’s at least one-story and 16 feet in height. Depending on your residential zoning code, you may be able to build two stories

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Parking

Generally, conversion ADUs and junior ADUs don’t require any parking. Attached and detached ADUs will require 1 parking space, unless your project qualifies for an exemption from the parking requirements.

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Number of ADUs allowed

If you have a single-family home, you can for the most part have one or two ADUs on it. The number of ADUs allowed on multi-family properties depends on the type of ADU constructed and how many dwelling units are already on the property.

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Minimum Lot Size

The good news is that your property can be any size and be eligible for an ADU. There are no minimum lot size restrictions.

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Allowed locations

Generally, you can have an ADU on your property if residential uses are allowed on it, although exceptions may apply. Also, you must have an existing or proposed single-family home on your property or an existing multi-family building (which is a fancy way to say a duplex, triplex, or other type of apartment or condo building).

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Renting the ADU

Yes, your ADU can be rented out, although most cities don’t allow short-term rentals of ADUs. This means you can probably only rent your ADU out for a period of month or longer.

Generally, the property owner will only have to live on the property if a JADU is built on it.

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Duplex and Triplex

You may be able to build based on how your property is zoned. You’ll need to call your local zoning department to confirm.

Select your city to learn more ADU building

More cities coming soon