Build an ADU in San Jose, California

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Overview

San Jose is located in Santa Clara County in California. San Jose has a total
population of 945942 over a land mass of 176.53 Square Miles. When it comes to
ADUs, the city allows for 1+ ADUs on a given property, and a square footage of
850-1,000 sf

Number of ADUs Allowed

1+

Size of ADU Allowed

850-1,000 sf

Types of ADUs Allowed

Detached, Junior, Attached

Permit Cost

Coming Soon

Number of ADUs allowed

Under state law, each single-family home may now add at least one Accessory
Dwelling Unit. Owner occupied single-family lots may add one Accessory Dwelling
Unit and one JADU. Multi-family lots, per every four existing residential units,
may add one Accessory Dwelling Unit, so long as the existing units were legally
established.

Property Requirements

Residential lots will be allowed to create up to 850 sqft for a one bed ADU or
up to 1,000 sqft for a two bed ADU, regardless of the underlying zoning
standards of the property. A JADU is allowed up to 500 sqft. According to
Califronia Residential Code, the minimum size of any living unit is 150 sqft
(including ADUs and JADUs). ~ AB68 & AB881 Update

Types of ADUs Allowed

Attached ADU

An attached ADU is one that is attached to your house. Also know as Addition ADUs or “bump-out ADUs. These types of ADUs can be accessed from the primary house with a door in the connection point, but also can be independent of the main home.

Detached ADU

A detached ADU is not connected to your primary house. The dwelling needs to be within your property setbacks and allowable building size (both height and square footage).

Junior ADU

Junior Accessory Dwelling Units (JADUs) are named this way because they are small (up to 500 square feet).

In California, the recent state bills AB68 and AB 881 permits both an ADU and a Junior ADU (JADU) on the same lot with a proposed or existing single-family dwelling. This means you can have two units on your lot: ADU, and JADU.

Property Requirements

Ownership
Owner-occupancy will not be required for new ADUs (conversion and new
construction) built between 2020 and 2025. ~ SB13 Update
Number of ADUs Allowed
Under state law, each single-family home may now add at least one Accessory
Dwelling Unit. Owner occupied single-family lots may add one Accessory Dwelling
Unit and one JADU. Multi-family lots, per every four existing residential units,
may add one Accessory Dwelling Unit, so long as the existing units were legally
established.
ADU Size
Accessory Dwelling Unit projects on single family or multi-family residential
lots will not be subject to the minimum lot size of the underlying local zoning
code or by special ordinance. ~ AB68
Parking
Parcels which convert an existing garage to an Accessory Dwelling Unit (ADU) or
Junior ADU will not be subject to replacement parking requirements. ~ AB-68
Height
Attached – Same requirement as the zoning district Detached - One story, 18 feet
maximum and 14 feet average (20.30.150.J.5)
Fire Safety
Fire sprinklers are required if required in the primary home.
Utility Connections
Local health officer approval where a private sewage disposal system is being
used, if required. (State requirements)
Aesthetic
Detached units do not need to meet any specific design standards. Attached ADUs
and detached ADUs on properties listed on the Historic Resources Inventory must
incorporate architectural style and elements of the primary dwelling.
Set backs
The maximum required setback for a detached new construction Accessory Dwelling
Unit shall be no more than 4 ft from the rear and side property lines. Setbacks
will not be required for Accessory Dwelling Units and Junior Accessory Dwelling
Units converted from existing space that was legally eastablished. Attached
Accessory Dwelling Units and conversions from existing space to be expanded will
be required to comply with the setbacks of the underlying zone. ~ According To
AB68

Design Review

Ministerial review process. Allowed by right in accordance with zoning and
building code.

Next Steps

To get started on your ADU, here are some first steps.

Call Your City

Search Google for your city’s contact number. eg “City of {Phoenix} Residential Permits Contact Number”

You can call the main line and get directed to the permitting department.

Ask these questions...

1) Can I put a secondary home on my lot (Accessory Dwelling Unit)?
2) What are my livable setbacks, and ADU size regulations?
3) Can I put a prefabricated guest house on my property?

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