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ADUs & JADUs

Overview
Monterey City Code Section 38-112.6, Accessory Dwelling Units and Junior Accessory Dwelling Units, was recently added by Ordinance 3641, which was adopted on November 2, 2021, and codified on December 2, 2021. The new ADU/JADU webpage summarizes this ordinance and explains how the City allows various types of ADUs on different properties.
Types of ADUs - ADU and JADU Checklist
  • Detached: The unit is separated from the primary structure.
  • Attached: The unit is attached to the primary structure.
  • Converted Existing Space: Space (e.g., master bedroom, attached garage, storage area, or similar use, or an accessory structure) on the lot of the primary residence that is converted into an independent living unit.
Junior Accessory Dwelling Unit (JADU)
JADU Definition: A dwelling unit no larger than 500 square feet, includes an efficiency kitchen, and is entirely contained within the walls of an existing or proposed single-family residence (including attached garages). The JADU either includes its own sanitation facilities, or shares sanitation facilities with the existing residence.
ADU-Examples

Benefits of ADUs
  • Affordability: ADUs are an affordable type of home to construct in California because they do not require paying for land, major new infrastructure, structured parking, or elevators.
  • Efficiency: ADUs can provide as much living space as many newly-built apartments and condominiums, and they’re suited well for couples, small families, young people, and seniors.
  • Income: ADUs can provide a source of income for homeowners. ADUs can also increase property value.
  • Flexibility: ADUs give homeowners the flexibility to share independent living areas with family members and others, allowing seniors to age in place as they require more care.
  • Privacy: ADUs allow extended families to be near one another while maintaining privacy.
  • Housing options: ADUs provide a method to build more housing quickly, within existing neighborhoods while preserving neighborhood character, and without increasing density. Building a new ADU usually takes a few months, as opposed to a new housing subdivision that could take two years or more.
Where are ADUs and JADUs allowed?
  • ADUs can be developed on a property with an existing or proposed single family residence or multifamily structure that is zoned to allow residential uses.
  • Can be attached, detached, or built within the existing structure.
  • See below "Regulations and Standards" for more detailed information.
Specifics

Regulations and Standards

Where are ADUs and JADUs allowed
Click on the type of ADU you are interested in to view its requirements. The following include summaries of most - but not all - development standards for constructing an ADU and/or JADU on your property. All ADUs must comply with the "Universal Requirements" included lower on this page.
New Detached or Attached ADU at a Single-Family Residence
  • 850 sf maximum for a studio or one bedroom ADU
  • 1,000 sf maximum for a two or more bedroom ADU
  • Needs separate exterior access
    • Up to 150 square feet of exterior additions are allowed to accommodate separate access
  • Cannot be a rental unit for less than 30 days
  • Please also see “Universal Requirements”, below.
New JADU at a Single-Family Residence
  • Must be located entirely within the existing structure
  • 500 sf maximum
  • Needs separate exterior access
    • Up to 150 square feet of exterior additions are allowed to accommodate separate access
  • Must have an efficiency kitchen (sink, food counter, appliances)
  • May, but not required to, include separate sanitation facilities (bath, sink, etc.).
    • If it does not include separate sanitation facilities, the primary residence’s bath and sink must be shared with the ADU residence.
  • Cannot be a rental unit for less than 30 days
  • If the JADU removes a garage parking space, replacement (covered or non-covered) parking must be provided.
    • If the replacement parking is uncovered and located within the driveway, the space should be at least 9ft x 18ft and cannot be located within the front yard setback nor extend into the public right-of-way.
  • Owner occupancy is required in either the JADU or single-family residence.
    • Specifically, prior to issuance of a building permit for a JADU, the owner must record a covenant in a form prescribed by the City attorney, which will run with the land, filed with the Building Department. The document will additionally certify that the JADU cannot be sold separately from the primary residence, cannot exceed the size restrictions, and either the primary residence or JADU must be the owner’s bona fide principal residence, unless the owner is a governmental agency, land trust, or housing organization.
  • Please also see “Universal Requirements”, below.
New ADU and JADU at a Single-Family Residence
  • For the ADU:
    • The maximum size of the ADU would be 800 square feet (to allow for an ADU + JADU)
    • Whether attached or detached, it must have separate exterior access
    • Cannot be a rental for less than 30 days
  • For the JADU:
    • Must be located within the existing structure
    • 500 sf maximum
    • Needs separate exterior access (minimal exterior additions are allowed)
    • Must have an efficiency kitchen (sink, food counter, appliances)
    • May, but not required to, include separate sanitation facilities (bath, sink, etc.). 
  • If it does not include separate sanitation facilities, the primary residence’s bath and sink must be shared with the ADU residence.
    • Cannot be a rental unit for less than 30 days
    • If the JADU removes a garage parking space, replacement (covered or non-covered) parking must be provided. (insert link to 112-6.4.f)
  • If the replacement parking is uncovered and located within the driveway, the space should be at least 9ft x 18ft and cannot be located within the front yard setback nor extend into the public right-of-way.
    • Owner occupancy is required in either the JADU or single-family residence.
  • Specifically, prior to issuance of a building permit for a JADU, the owner must record a covenant in a form prescribed by the City attorney, which will run with the land, filed with the Building Department. The document will additionally certify that the JADU cannot be sold separately from the primary residence, cannot exceed the size restrictions, and either the primary residence or JADU must be the owner’s bona fide principal residence, unless the owner is a governmental agency, land trust, or housing organization.
  • Please also see “Universal Requirements”, below.
New ADU(s) on a parcel with a Multifamily Building 
  • Only one new ADU may be developed on the parcel
  • Portions of an existing multifamily building that are not used as livable space may be converted into ADUs, totaling at least 1, or as many as up to 25 percent of the number of existing, legal multi-family dwelling units of the building
  • Sites cannot have more than two detached ADUs (e.g. one newly developed ADU in addition to one detached garage or other space converted to an ADU)
  • ADUs may be up to 16 feet in height and have at least 4 feet rear and side setbacks.
    • Exceptions to this height limit can be applied for within the R-3 zoning district. See “Universal Requirements - Height” below for additional information.
  • Please also see “Universal Requirements”, below.
New ADU at a Parcel Designated as a Historic Resource (H-1, H-2  or HD Zoning)
  • If attached, locate the ADU at the rear of the structure
  • If detached, locate the ADU at least 10 feet behind the rear of the main historic structure
  • Not match the exterior finish of the historic building
  • Locate new exterior doors for the ADU so that they do not face the front yard
  • Please also see “Universal Requirements”, below.
Universal Requirements 
  • Kitchen and Sanitation Minimums
    • ADU: Requires at least one efficiency kitchen (sink, food counter, appliances) AND at least one sanitation area (sink, bath)
    • JADU: Requires at least one efficiency kitchen (sink, food counter, appliances)
  • Setbacks
    • Newly constructed: 4 feet minimum from rear and side
    • Within existing structure (building conversion): no setback required, unless for fire or ingress/egress
  • Height
    • Attached/Detached ADU: 16 feet maximum
    • Second Story ADU/Above Garage ADU (exclusively within the R-3 zone): 25 foot maximum, and:
    • With approval of an Architectural Review Permit  
    • Garage must be at ground level
    • No windows or openings are allowed within 4 feet of the property line
    • Windows within 10 feet to the property line must be either opaque and inoperable, or clerestory windows at least 6 feet above floor level
  • Entrances
    • ADUs must have a separate entrance from the primary structure(s)
  • Parking
    • One parking space must be provided per unit onsite, unless:
      • Located within 0.5 mile of a transit stop
      • Located within 1 block of a car share location
      • Located within the primary residence 
      • Located within an architecturally and historically significant historic district
      • Located on a parcel where on-street parking permits are required buy not offered to the occupant of an ADU
      • An existing garage/carport/covered parking is demolished in conjunction with the construction of or replaced by an ADU
  • Water
    • ADUs are not permitted on a parcel with inadequate water or sewer services.
    • Verification from the Monterey Peninsula Water Management District indicating that sufficient on-site water credits are available for the ADU, is required. This verification must be submitted with the application for a building permit.
  • Design
    • ADUs must be constructed with façade materials identical in color, similar in texture, and similar in appearance to the primary dwelling.
    • This requirement includes – but is not limited to – roofing, siding, windows, and doors, among other features.
  • Roof Pitch
    • ADUs must match the roof pitch and roof form of the primary dwelling.
  • Building Code
    • ADUs must conform to State and local building code requirements.
    • Fire sprinklers may not be required for the ADU unless they are required for the primary dwelling.

Step-by-Step to Build an ADU

Step Process
1. Background Research
  • Gather Information
    • Check water availability at your property – contact the Monterey Peninsula Water Management District to confirm the number of credits at your property: (831) 658-5601
  • Prepare a preliminary Site Plan to verify feasibility
  • If desired, consult with City staff to check your concept (Planning or Building & Safety Department)
  • Assemble your project team
  • Architect or qualified consultant prepares initial design
  • Review initial design with City staff
  • Refine plan 
2. Design
  • Construction plans prepared by architect or qualified consultant
  • Comply with applicable provisions of California Building Code
  • Comply with City Code
3. Expedited Permitting
  • Obtain Application for a building permit from the City’s Building & Safety Division 
  • Plan review by City staff
  • Complete requested corrections or comments on plans
  • Re-submit plans for further review, if required
  • Pay any applicable fees
  • Permit approval and issuance
4.    Construction
  • You or your contractor begins work
  • Obtain necessary inspections as construction progresses
  • Obtain final inspections and sign-off
5.    Move-in!

Informational Links

The following links and documents are provided for informational purposes only. 

Accessory Dwelling Unit Handbook from the California Dept. of Housing & Community Development: https://www.hcd.ca.gov/policy-research/docs/adu_december_2020_handbook.pdf
For additional guidance, ADU Handbooks, or possible ADU floor plans for public use, please go to the California HCD website: https://www.hcd.ca.gov/policy-research/accessorydwellingunits.shtml
Discover the potential for an ADU on your property – ADU possibilities on your lot: https://build.symbium.com
“The ABCs of ADUs: A guide to Accessory Dwelling Units and how they expand housing options for people of all ages” by AARP: https://www.aarp.org/content/dam/aarp/livable-communities/livable-documents/documents-2019/ADU-guide-web-singles-071619.pdf 
ADU Finance Guide for Homeowners: https://www.hcd.ca.gov/policy-research/accessorydwellingunits/docs/cc%20adu%20finance%20guide%20for%20homeowners%20v5%203.18.21_ada.pdf
American Institute of Architects, California – ADU Resource Center: http://plus1house.org
ADU Professionals: https://accessorydwellings.org/adu-professionals