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
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
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.
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
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.
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
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
What City permits and fees apply?
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.
Fire Sprinkler Permit. For ADU proposals
requiring fire sprinklers, separate plans shall be submitted
for fire sprinkler design to the Fire Department.
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
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.
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
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.