Fairfield ADU Resources

Homeowner's guide to building an ADU in Fairfield

🏠 Over 258 ADUs built in Solano County!

Type of ADUs

Explore what ADU works for you

1
Junior Accessory Dwelling Unit (JADU)
A Junior ADU (JADU) is an ADU of no more than 500 square feet. A JADU must be within a proposed or existing single-family home or accessory structure, such as a garage.

Unlike ADUs, JADUs may share a bathroom with the single-family home and must only meet “efficiency kitchen” requirements.
2
Accessory Dwelling Unit (attached / detached)
Detached ADUs are located in free-standing buildings that are separate from the main single-family home or multi-family building.

Attached ADUs involve adding on to a single-family home.

ADUs are typically no more than 1,200 square feet.
3
Attic Conversion
An Attic Conversions transforms your unused attic space into a livable, independent housing unit, complete with necessary amenities, providing extra living space or a rental opportunity without altering your home's footprint, enhancing functionality and potentially increasing your property's value
4
Basement Conversion
A Basement Conversion ADU turns your lower level into a self-contained living area, ideal for renting out or housing family, with added privacy and use of existing space, often boosting home value and utility without changing the exterior structure of your home.
5
Garage Conversion
A Garage Conversion ADU repurposes your garage into a separate, functional living unit, ideal for renting or family use. It leverages underutilized space, potentially increasing your property's value and utility, while preserving the home's external facade, offering a practical, less intrusive approach to expanding living areas.
6
SB9 Lot Split
California's SB9 enables homeowners to split their single-family lot, allowing the construction of up to four residential units, maximizing land use, increasing housing availability, and offering potential income streams while adhering to local zoning and space regulations.

Development Standards for an ADU

Know what's allowed on your property

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Setbacks

California state law dictates a minimum 4-foot setback from the rear and side yard for Accessory Dwelling Units (ADUs). The distance between an ADU and the primary residence isn't set at the state level and may be subject to local regulations.

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Square Footage

In California, you can build an Accessory Dwelling Unit (ADU) up to 1,200 square feet, subject to local regulations. However, state law mandates that local jurisdictions must allow ADUs of at least 800 square feet and 16 feet in height.

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Height

Generally, you should be able to build an ADU that’s at least one-story and 16 feet in height. Depending on your residential zoning code, you may be able to build two stories

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Parking

Generally, conversion ADUs and junior ADUs don’t require any parking. Attached and detached ADUs will require 1 parking space, unless your project qualifies for an exemption from the parking requirements.

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Number of ADUs allowed

If you have a single-family home, you can for the most part have one or two ADUs on it. The number of ADUs allowed on multi-family properties depends on the type of ADU constructed and how many dwelling units are already on the property.

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Minimum Lot Size

The good news is that your property can be any size and be eligible for an ADU. There are no minimum lot size restrictions.

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Allowed locations

Generally, you can have an ADU on your property if residential uses are allowed on it, although exceptions may apply. Also, you must have an existing or proposed single-family home on your property or an existing multi-family building (which is a fancy way to say a duplex, triplex, or other type of apartment or condo building).

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Renting the ADU

Yes, your ADU can be rented out, although most cities don’t allow short-term rentals of ADUs. This means you can probably only rent your ADU out for a period of month or longer.

Generally, the property owner will only have to live on the property if a JADU is built on it.

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Duplex and Triplex

You may be able to build based on how your property is zoned. You’ll need to call your local zoning department to confirm.

1

See what you can build

See what you can build within your project setbacks and size requirements.
2

Find a ADU plan that works

Find a selection of designs that match your taste and comply with local regulations.
3

Plan your budget and get financing

Utilize our resources for zoning, design planning and visualization.
4

Hire a building professional

Choose from our vetted service providers for construction, financing, and more.
ADU Plans
Types of ADUs
Zoning
Resources

Browse ADU Plans

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Pre-Approved Plans: There are no Pre-Approved Plans for this Jurisdiction. Check back soon for new ADU plans that are Pre-Reviewed or browse the plans below. New plans will be added regularly so check back often.
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Learn More About Building an ADU (Resources)

ADU Financing

Flexible Lending Options

We offer multiple lending solutions for ADU projects, considering both the future value and potential rental income to assist more homeowners in qualifying. Our programs are designed to be inclusive, factoring in your home's expected post-project value. Importantly, you can secure funding without the need to refinance your existing mortgage, courtesy of our construction loan partner.

This streamlined financing can make the difference in realizing your ADU addition while maintaining your current home loan structure.

Explore Your Financing Options
Site Planner

Find out what you can build on your property

Embarking on an ADU project begins with the perfect placement. Our Property Planner is an intuitive tool designed to help you visualize your future ADU on your property.

It considers local zoning laws, setbacks, and unique site conditions to suggest the optimal location for your new unit. You can experiment with different spots on your property, ensuring compliance and maximizing both functionality and aesthetics. By providing a clear visual layout, the tool aids in strategic decision-making, helping to streamline the planning phase of your ADU project.

Visualize Your ADU Placement
ADU Cost Calculator

Budget Smarter for Your ADU

Navigating the financials of building an ADU can be complex, but our Cost Calculator demystifies the process. By inputting a few details about your planned ADU, you’ll receive an instant estimate that helps you understand the financial commitment involved.

This tool takes into account various factors, including materials, labor, size, and design preferences, giving you a comprehensive and tailored budget outline. It’s designed to help you plan efficiently, avoid unexpected costs, and align your ADU project with your financial reality.

Calculate Your ADU Budget