Click to Home
Go To Search
Planning Building and Code Enforcement
San Jose Home
Secondary Units or Accessory Dwelling Units (ADUs)

Secondary units  also called accessory dwelling units, ADUs, or granny flats are small dwelling units that can efficiently leverage the land and existing infrastructure of single-family neighborhoods without significant change to the character of a neighborhood. ADUs may provide an income opportunity for homeowners; may help people provide housing to their extended family members or disabled persons; and may create more affordable housing opportunities for our community.

On June 19, 2018, the City Council will consider changes to the zoning rules and development standards for ADUs in San Jose; the main impact of these changes, if approved, would enable more single-family properties to qualify for an ADU. Current development standards for ADUs in San Jose are found in Section 20.30.150 of the Zoning Ordinance

ADUsProperties that Qualify for an ADU
The City developed a presentation on the current and proposed requirements for Accessory Dwelling Units (ADUs). View the presentation here.

You can use the Secondary Unit Review Worksheet, which applies current zoning rules, to help determine eligibility for an ADU. Again, please note that these rules may change pending the outcome of the City Council's June 19, 2018 decision.

A Building Permit is required to build an ADU. Your project will be reviewed for conformance with the Zoning Ordinance and California Building Code. Applicants should also review these fire-related directives:

Building Review Requirements for Fire Separation for Secondary Units 
Fire Department Review Requirements for Secondary Units

Permit Fees and Other Fees for ADUs
Permit fees for an ADU vary based on the project scope; see the Building Division Fee page for more information.

It should be noted that in addition to a building permit fee, applicants for an ADU will be required to pay School Fees and Park Impact Fees. For information on School Fees, visit For information on Park Impact Fees,
view the map that shows the fees that vary according to location.  

2018 Secondary Unit Ordinance Update
Based on public input, Planning staff proposed updates to Section 20.30 of the Zoning Code to modify the lot size, setbacks, height, parking exemptions, and other provisions for ADUs. At its
May 9, 2018 meeting, the Planning Commission held a public hearing and reviewed the proposed changes for ADUs; view the memorandum. The commission voted unanimously to recommend that the Council adopt the proposed changes; the item will be heard by the Council on June 19, 2018. 

Four community meetings inviting public input on updating the ordinance have been held:
- Monday, February 12, 2018 from 6.30 p.m. - 7.30 p.m. at City Hall 
- Thursday, March 22, 2018 from 5.30 p.m. - 6.30 p.m. at the Almaden Community Center
- Monday, March 26, 2018 from 6.30 p.m. - 7.30 p.m. at the Alum Rock Community Library
- Thursday, March 29, 2018 from 7.00 p.m. - 8.00 p.m. at the Willow Glen Community Center

Through these meetings, City staff identified the following considerations for the proposed updates:


Existing Regulations

Considerations and Proposed Updates

Zoning District Designation

Allowed in R-1, R-2, and PD (subject to R-1 standards) zoning districts, comprising of single-family residences.

Allow in R-M zoning district, (and on PD lots subject to R-1 standards and lot size), where single-family residences exist.

Minimum Lot Size

5,445 sq.ft. – for both attached and detached units

Allow on lots with areas between 3,000 sq.ft. and 5,445 sq.ft. with restrictions on unit size. Not allowed on lots <3,000 sq.ft.

Minimum Setbacks from Property Line

0 (conversion), 5 feet

0 feet for existing structures (in compliance with Building and Fire Code); Allow 5 feet minimum from the side and rear property line for new units and for units constructed above a garage.  

Maximum Height

Single Story – 18 feet maximum, 14 feet mid- roof

Allow up to 22 feet maximum (measured from grade to top of roof) for a detached unit atop an existing garage/accessory structure.

Rear Yard Coverage

Not to exceed 40% for detached Secondary Unit, Accessory Building and Structures (except for pools)

No change proposed.

Detached Secondary Unit - Location

In rear yard, and at least 6 feet away from primary dwelling. Can be attached only to a detached garage.

Allow ADU to be attached to and converted from other existing accessory buildings in addition to garages. 

Maximum unit square footage based on lot size

600 sq.ft. (5,445 - 9,000 sq.ft.); 650 sq,ft, (9,001 - 10,000);

800 sq,ft, (10,001+)

Limit to 600 sq.ft. (3,000 – 5,445 sq.ft,)

700 sq.ft, (5,445 - 9,000 sq.ft,); 
800 sq.ft, (9,001 - 10,000 sq.ft,);

900 sq.ft, (10,001+ sq.ft,)

Number of Bedrooms

One bedroom or combined living and sleeping area

One bedroom with common living space or combined living and sleeping area

Floor Area

Attached dwelling unit shall NOT exceed 50% of the existing living area of the primary dwelling

Attached dwelling units shall not exceed 50% of the existing or proposed living area of the primary dwelling. 

Parking requirements and driveway width

Parking configurations in conformance with State Law

Allow parking within front and side setbacks for a garage conversions into a secondary unit.

Design tandards


Match appearance, and match roof form and pitch

Require visual compatibility with existing primary dwelling.

Junior accessory dwelling unit

Not Allowed

Allow maximum 500 square feet limited to up to 50% of the primary dwelling unit

Front Yard Paving

Section 20.30.440

No more than 50% of the front setback shall be paved with asphalt, cement or any other impervious surface.

Allow no more than 50% of the front setback shall be paved with asphalt, cement or any other impervious or pervious surface.

Reduction in required off-street parking spaces

Section 20.90.220

B(1)(a) No more than one dwelling occupies the lot.

Allow no more than one dwelling, in conjunction with an ADU, to occupy the lot.

Secondary unit addition to a single-family lot located on the Historic Resources Inventory

Requires Single-Family House Permit

Waive requirements for a Single-Family House Permit for new detached Secondary Unit or for conversion of existing accessory structure with no exterior alterations.



Add definitions for conversion, Single-Family dwelling unit.