An Accessory Dwelling Unit (ADU) — sometimes called a granny flat, second unit, or casita — is a smaller, self-contained home on the same property as an existing residence. ADUs can be attached or detached from the main home and are generally between 150 and 1,200 square feet. They can provide housing for family members, generate rental income, or offer a downsizing option later in life. ADUs are allowed on most residential properties in California with limited exceptions.

Getting Started

The following resources can help you explore whether an ADU is right for your property and guide you through the process.

Symbium Tool

 Find out what you can build on your property, including ADU size, setbacks, and other requirements specific to your lot. Access the Symbium Tool.

Second Unit Resource Center

A step-by-step workbook developed in partnership with 21 Elements and Home for All, guiding homeowners from initial planning through permitting and becoming a first-time landlord. Visit the Second Unit Resource Center.

ADU Plans Gallery

 Browse pre-approved and designer ADU plans to find inspiration or a design you want to use. Pre-approved plans have been reviewed for building code, reducing permitting review time to 30 days. The gallery includes site-built and prefabricated options across a range of sizes, styles, and price points. Access the Pacifica ADU Plans Gallery.

Note: All plans — including pre-approved plans — still require customized site planning and permitting based on your specific property, including lot placement, emergency access, and foundation plans.

Junior ADU Deed Restriction Form If you are adding a Junior ADU (JADU), this form is required as part of the permitting process. Download the Junior ADU Deed Restriction Form.

Are You in the Coastal Zone?

Properties within the Coastal Zone may require an Administrative Coastal Development Permit (CDP) prior to building permit submittal. Contact the Planning Division to confirm whether your property requires an Administrative CDP before you apply.

Frequently Asked Questions

What is the difference between an ADU and a Junior ADU? An ADU is a fully self-contained unit with its own kitchen, bathroom, and entrance, and can be attached or detached from the main home. A Junior ADU (JADU) is smaller — up to 500 square feet — and is created within the existing walls of the primary residence, such as from a converted bedroom or garage space.

What are pre-approved ADU plans? Pre-approved plans have been reviewed for building code compliance by a local, state, or federal agency. Using a pre-approved plan can reduce the building permit review period to 30 days. Pre-approved plans are general and not tied to a specific property — they cannot be significantly customized and still qualify for expedited review.

Can I use a plan that isn't pre-approved? Yes. The ADU Plans Gallery also includes designs from trusted designers that have not been pre-reviewed for building code. You can use these plans and proceed through the standard permitting process, which may still save time and money compared to a fully custom design.

What do I do after I choose a plan? Contact the designer directly to purchase or access the plans, then work with the designer or another qualified professional to complete site planning and submit your building permit application.

How much do plans cost? Designers set their own pricing. The gallery includes options ranging from free plans provided by government agencies and nonprofits to paid plans and prefabricated unit packages.

I'm having trouble using the ADU Plans Gallery. Visit ADUAccelerator.org/docs/homeowners for instructions and support articles or contact support@aduaccelerator.org with a description of your issue.

Contact the Planning Division

For questions about ADUs or the permitting process, contact the Planning Division at planningdivision@pacifica.gov or (650) 738-7341.