What is an ADU?

An accessory dwelling unit (ADU), also known as a “mother-in-law” or “granny flat,” is an attached or detached residential dwelling unit that provides complete independent living facilities for one or more persons on the same parcel as the main dwelling unit. This includes permanent provisions for living, sleeping, eating, cooking, and sanitation. An ADU can be an efficiency unit, as defined in Section 17958.1 of Health and Safety Code, or a manufactured home, as defined in Section 18007 of the Health and Safety Code.

Can I have an ADU on my property?

ADUs may be permitted on lots where there is an existing or proposed single or multi-family dwelling.

What is a JADU?

A series of new State housing laws took effect January 1, 2020 which created a new land use definition for a junior accessory dwelling unit (JADU). A JADU is a residential dwelling unit that is no more than 500 square feet in area, contained entirely within an existing single-family residence, and can have separate sanitation facilities from, or shared sanitation facilities with, the existing residence.

 –Illustration by Alfred Twu

Can I have a JADU on my property?

One detached ADU and one JADU may be permitted on any lot with an existing single-family dwelling.

Let’s Get Started!

Step One

Find your zoning district using the City’s Public Interactive Zoning Map

Step Two

Review the Chico ADU Development Standards to determine the size, placement and design requirements for your ADU project.

Step Three

Find your best fit! When it comes to ADU designs, you’ve got two choices:

OPTION A – CUSTOM DESIGN

​For some people, the project is half the fun! If you’re looking to customize the size, layout and look of your ADU, hire an experienced professional to draw the plans to bring your dream design to life!

OPTION B – PRE-APPROVED ADU PROGRAM

​Looking to save a little time and expense? Check out the City’s ADU Catalog  to browse the designs that have been pre-approved by the Building Division.

Step Four

Review and complete the ADU Details Questionnaire & Site Plan Checklist. When your ADU plans address all of the items on the checklist, you’re ready to submit your construction plans.

*** Advisory – Preapproved ADU Building Plan Will No Longer Be Available  Starting in January 2023***

The updated California Building Code will go into effect in January 2023, and the current portfolio of preapproved ADU plans will no longer be compliant with the updated Building Code starting in January.  City staff is researching grant funding sources to update some of the preapproved ADU plans for compliance with the new Building Code.  If grant funds are secured, it is anticipated that there will be fewer ADU plan options available and it may be several months until the plans are available.