Accessory Dwelling Units (ADUs) and Junior Accessory Dwelling Units (JADUs) provide housing opportunities within existing neighborhoods that are more affordable due to their smaller size and use of existing infrastructure. These additional units help diversify the market for renters while proving supplemental income for homeowners, thus increasing affordability throughout the City.

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.

Want to learn more?

Check out staff’s answers to the most frequently asked questions regarding accessory dwelling units: ADU FAQs.

Should you still have questions, contact the Planning Division at (530) 879-6800 or by email.

Now Available – Pre-Approved ADU Plans

With grant funds secured from the State Department of Housing and Community Development (SB 2 “Building Homes and Jobs Act”), the City had a series of ADU plans designed (13 design variations), plan checked and are now available “pre-approved” to the public for use…free of charge!

Interested property owners will first choose between three ADU sizes: 496, 599, or 749 square feet. Using the ADU Catalog, select from the five design options available for the 496 s.f. ADU (Vecino, Chico, One Mile, Esplanade, Honey Run), four designs for the 599 s.f. ADU (Manzanita, Hooker Oak, Oleander, Sycamore), or four designs available for the 749 s.f. ADU (Barber, Sutter, Stansbury, Bidwell). ADU plans come in with a universal/accessible floor plan option with wider and accessible doorway entries. These ADU plans come pre-approved by the Building Division, meaning a stream-lined permit process and significant savings for the interested ADU owner. 

Once you’ve decided on your preferred ADU design, a site plan must be prepared showing the proposed location of the ADU on your property. Please refer to the ADU Homeowner's Guide for step-by-step instructions and information regarding fees associated with your project.  

What City permits and fees apply?

1. Building Permit.  A building permit is required for all ADUs, including conversion of existing living space or garage area. Contact the City’s Building Division at (530) 879-6700 to determine what Building fees will be applied to your project.  
2. Fire Sprinkler Permit. For ADU proposals requiring fire sprinklers, separate plans shall be submitted for fire sprinkler design to the Fire Department.
3. School Impact Fees. All ADUs (conversions and new construction) may be subject to school district fees. Currently, the fees are $3.79 per square foot. As of July 20, 2020, school district fees will increase to $4.08 per square foot.
4. Development Impact Fees. No development impact fees shall be assessed on ADUs up to 750 square feet in size. For ADUs greater than 750 square feet, impact fees will be assessed at a rate proportional to the main residence. Contact the Building Division for more information on which impact fees apply to your project.

Universal Design/Accessibility

The preapproved ADU plans are available in a Universal Design/Accessibility floor plan design option with a step-free entrance, sufficient maneuvering space for a wheelchair in a bedroom, kitchen, entertainment area, and admittance to a full bathroom, and ample room to pass through 32-inch doorways.

Can we have your permission to photograph construction of your ADU?

While you are certainly under no obligation, the City of Chico kindly requests your permission to obtain photographs and live filming of your ADU during construction and hopefully a positive testimonial from you or others on the ease of constructing the ADU and any savings of time and money utilizing the City’s preapproved ADU plan program.  We believe your positive first-hand experience in getting underway with your ADU will help get the word out to others in the community that may be interested in following your lead.  Thank you for your interest in the City’s preapproved ADU program and we hope that you will sign the attached release allowing the City to photograph and film the construction and completion of your new ADU.     

ADU Resources

Chico ADU Development Standards

ADU FAQs

Details Questionnaire & Site Plan Checklist