Attached ADU
Attached ADUs in Sacramento, CA
Definition
What is a attached adu?
An attached ADU is a complete living unit built as an addition to your existing house, sharing at least one wall but with its own entrance, kitchen and bathroom. In Sacramento it is a strong fit when your backyard is small, when you want to reuse existing utilities, or when a family member needs to be close by.
Who is a attached adu best for?
- Lots without enough backyard depth for a detached unit
- Multigenerational households who want a separate door but a short walk
- Homeowners who want to tie into existing sewer, water and electrical close by
- Owners pairing the ADU with a remodel of the main house
How big can a attached adu be?
Attached ADUs are generally limited to a percentage of the main home's living area, often 50 percent, with an overall cap similar to detached units. A unit up to 850 square feet for one bedroom, or 1,000 square feet for two bedrooms, is generally allowed under state law even where local percentages are tighter. We confirm the exact limits for your parcel.
How long does a attached adu take?
Most attached ADUs take about 8 to 13 months from first site visit to move-in. Design takes longer than a stand-alone unit because we are tying a new structure into an existing roof, foundation and framing, but utility work is usually simpler.
How much does a attached adu cost in Sacramento?
$100,000 to $300,000
Attached ADUs in the Sacramento area typically range from $100,000 to $300,000. The roof tie-in, the condition of the existing structure and how much of the main house is touched by the work drive the price.
Costs and financing optionsRules in plain English
What are the Sacramento rules for a attached adu?
Rules vary by jurisdiction and change often. Call us to confirm what applies to your property.
- Sizeoften limited to 50% of the main home's living area, with state minimums that guarantee a reasonable unit.
- Setbacks4 ft side and rear setbacks typically apply to the new addition.
- Entrancethe ADU needs its own exterior entry. An interior connecting door may be allowed but is not required.
- Fire separationthe shared wall and ceiling need fire-rated assemblies between the two units.
- Parkinggenerally waived near transit and when converting existing space.
- Owner occupancyrequirements are currently suspended through 2030.
How we build it
How we design, permit and build your attached adu
- 01
Read the existing house
We check the existing foundation, roof framing and panel before design, so the tie-in is planned, not discovered.
- 02
Design that looks original
Rooflines, siding and windows are matched so the addition looks like it was always there.
- 03
Separation done right
Fire-rated walls, sound control and separate utilities where required are drawn into the plans from day one.
- 04
Protect your household
We phase work to keep the main house livable, with clear notice before any shut-offs.
Is an attached ADU cheaper than a detached ADU?
Often, but not always. An attached ADU saves on utility trenching and one exterior wall, but tying into an older roof or foundation can add cost. On many Sacramento ranch homes from the 1950s through 1970s the tie-in is straightforward. On older homes with raised foundations, it takes more care. We price both options for your lot when it makes sense.
Ready to plan yours? See our full Design, Permit, Build process, browse design concepts, or read the Sacramento ADU rules guide.
Attached ADU gallery
Representative images. Completed project photos coming soon.
FAQ
Attached ADU questions
What is the difference between an attached ADU and a junior ADU?
An attached ADU is a new addition with its own full kitchen and bath and can be up to the allowed ADU size. A junior ADU is carved from space inside the existing home, is limited to 500 square feet and can share a bathroom with the main house.
Does an attached ADU need a separate entrance?
Yes. An attached ADU needs its own exterior entrance. An interior door to the main house can sometimes be included but is optional.
Can an attached ADU have its own utility meters?
It can, but separate meters are usually not required for attached units. Separate meters add cost, and we discuss the tradeoff if you plan to rent the unit.
Will my family be able to live in the house during construction?
In most cases yes. We phase the work and give advance notice before any planned water or power shut-offs.
Free quote
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916.505.2036ADU Design Center2230 26th Street, Sacramento, CA 95818Call to schedule your visit.
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