Accessory Dwelling Units
Accessory dwelling units ("ADU")s contribute needed housing to the City of Gilroy’s housing stock and enhance housing opportunities. ADUs and junior ADUs are allowed on single-family, duplex and multifamily dwelling zoned properties that include a proposed or existing primary residential dwelling.
How do I apply for a permit?
For general building permit questions, please call (408) 846-0451. Once you have your plans ready to go, you will Submit all Forms and Plans to PlanSubmittal@cityofgilroy.org.
Where can I find the City zoning regulations for an ADU?
(a) Short-term rentals are prohibited. An accessory dwelling unit shall not be rented for periods less than thirty (30) days.
(b) An accessory dwelling unit shall not be sold separately from the primary residential structure.
(c) Prior to the issuance of a building permit for an accessory dwelling unit and/or a junior accessory dwelling unit, the owner must record a deed restriction stating that any accessory dwelling unit on the property may not be rented for periods less than thirty (30) days and that any accessory dwelling unit may not be transferred or sold separately from the primary residential structure. In addition, the deed restriction for a junior accessory dwelling unit shall include an owner occupancy requirement in compliance with this article. However, there shall be no owner occupancy requirement imposed on an accessory dwelling unit that is permitted on or after January 1, 2020.
What is the difference between an ADU and a Jr. ADU?
- “Accessory dwelling unit” means an attached or a detached residential dwelling unit that provides complete independent living facilities for one (1) or more persons and is located on a lot with a proposed or existing primary residence. It shall include permanent provisions for living, sleeping, eating, cooking and a food preparation area (which may include countertop appliances), and sanitation on the same parcel as the single-family or multifamily dwelling is or will be situated.
- “Attached accessory dwelling unit” means a residential dwelling unit that is created as a result of internal conversion, addition, or combination thereof made to the primary residential dwelling unit.
- “Junior accessory dwelling unit” means a unit that is no more than five hundred (500) square feet in size and contained entirely within a single-family residence. A junior accessory dwelling unit may include separate sanitation facilities, or may share sanitation facilities with the existing structure.
How many ADUs can I have on a Single-family zoned property?
One (1) ADU is allowed when the property contains an existing or proposed primary single-family home. The ADU may be within, attached to, or detached from the proposed or existing primary dwelling; however it must have independent exterior access from the existing residence.
How many ADUs can I have on a Multi-family zoned property?
- Portions of the existing duplex or multifamily dwelling structure(s) that are not used as livable space (including, but not limited to, storage rooms, boiler rooms, passageways, attics, basements, or garages) may be converted for use as an ADU; provided, that the total number of units must not exceed twenty-five percent (25%) of the existing multifamily dwelling units or one (1) unit, whichever is greater.
- An owner may also construct up to a maximum of two (2) detached ADUs on a lot that has an existing permitted duplex or multifamily dwelling, subject to a height limit of sixteen (16) feet and four (4) foot rear yard and side setbacks.
- Each unit shall be limited in accordance with the maximum size parameters provided below.
What is my zoning district?
Please email the Planning Division with your address and we can look up your zoning for you.
What is the maximum square footage allowed?
- A detached accessory dwelling unit shall not exceed a maximum size of one thousand (1,000) square feet in floor area.
- An attached accessory dwelling unit, including internal conversions of existing primary living space, shall be permitted but shall not exceed fifty percent (50%) of the existing primary dwelling gross floor area, garage area excluded. Notwithstanding this requirement, an eight hundred (800) square-foot accessory dwelling unit shall be allowed.
What is the height limit?
- The maximum height for an accessory dwelling unit shall be one (1) story and sixteen (16) feet.
- The maximum height for a structure composed of a detached garage and an accessory dwelling unit that is proposed to be constructed above a detached garage shall be twenty-four (24) feet.
What are the setbacks for an ADU?
An accessory dwelling unit is subject to the design criteria and zoning requirements of the zoning district in which the existing primary dwelling is located, and as follows:
- An accessory dwelling unit must not encroach upon the required front yard area.
- A setback of four (4) feet from the side and rear lot lines shall be required for a newly constructed accessory dwelling unit that is not constructed in the same location and to the same dimensions as an existing structure.
- No additional zoning setback is required for conversion of an existing permitted accessory structure, living area, or garage space, or conversion of a structure that is constructed in the same location and to the same dimensions as the existing structure
Please email the Planning Division with your address and we can look up your zoning for you.
What are the parking requirements?
One (1) additional parking space shall be required for a newly constructed accessory dwelling unit, which may be located within the front setback, in tandem and in an existing driveway that provides at least eighteen (18) feet of clearance from the back of sidewalk. Parking in setback areas or tandem parking may be denied if found to be infeasible due to specific site or life safety conditions.
Notwithstanding the above, a parking stall will not be required for an accessory dwelling unit that meets any of the following criteria:
- The accessory dwelling unit is created as a result of the conversion of existing area of the single-family residence or existing permitted single-family residential accessory structure.
- An existing single-family residential garage, carport or parking structure is converted or demolished to accommodate an accessory dwelling unit in the same location.
- The accessory dwelling unit is within one-half (1/2) mile walking distance of a public transit station, such as a bus stop or train station.
- The property is within an architecturally and historically significant historic district.
- On-street parking permits are required in the area but not offered to the occupant of the residential accessory dwelling unit.
- A car share vehicle is located within one (1) block of the accessory dwelling unit.
Are there any design standards?
Accessory dwelling units are subject to the design standards and other zoning requirements of the zoning district in which the existing primary dwelling is located. Architectural review of an attached or detached accessory dwelling unit will be limited to the following:
- The design of the single-family residential accessory dwelling unit must be compatible with the existing primary dwelling. This may be achieved through use of the same architectural details, including, but not limited to, window styles, roof slopes, exterior materials, and colors. Architectural review shall not unreasonably restrict construction of the accessory dwelling unit.
- An accessory dwelling unit located within a historic site or neighborhood combining district will be subject to ministerial review for compliance with the design review criteria set forth in section 30.27.40 and must be consistent with the Secretary of the Interior’s Standards for the Treatment of Historic Properties.
- Outside stairways serving a second story accessory dwelling unit shall not be constructed on any building elevation facing a public street.
- No passageway will be required in conjunction with the construction of an accessory dwelling unit.
- An accessory dwelling unit must be built in accordance with the building code set forth in Chapter 6, except that any design, zoning, and building standards inconsistent with state requirements under California Government Code Section 65852.2 shall not apply.
What are the Junior accessory dwelling unit standards?
- Owner occupancy of the property shall be required. The owner must reside in the primary single-family residence, junior accessory dwelling unit or separate residential accessory dwelling unit constructed on the property in compliance with this article.
- One (1) junior accessory dwelling unit may be permitted per residential lot zoned for a single-family residential use; provided, that the lot has not more than one (1) existing or proposed single-family residence, and not more than one (1) attached or detached residential accessory dwelling unit if constructed in compliance with all applicable limitations of section 30.54.30.
- The unit must be constructed within the existing walls of an existing or proposed single-family dwelling.
- The square footage of the unit shall be at least the minimum size required for an efficiency unit, up to a maximum size of five hundred (500) square feet in floor area.
- A separate entrance from the unit to the exterior of the residence shall be provided. Internal connection may also be permitted.
- An efficiency kitchen must be provided in the unit which shall include all of the following:
- A cooking facility with appliances, which may be countertop appliances.
- A food preparation counter and storage cabinets that are of reasonable size in relation to the size of the junior accessory dwelling unit.
- The unit may include separate bathroom facilities or may share bathroom facilities contained within the primary residence.
- No separate utility connection, connection fee or capacity charge, or parking space shall be required for a junior accessory dwelling unit.
Are fire sprinklers required?
The installation of fire sprinklers shall not be required for an accessory dwelling unit if sprinklers are not otherwise required for the primary residence.
Are we able to use water & power from the existing residence?
Subject to Government Code Section 65852.2(f)(4), an accessory dwelling unit must have an independent electrical subpanel, water heating and space heating equipment within the unit or be readily accessible to the occupant on the exterior of the unit. The accessory dwelling unit must contain water, sewer and gas and/or electric utility connections that are in working condition upon its occupancy. The accessory dwelling unit may be serviced by the primary residence or may have separate utility meters.