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.
Let’s Get Started!
Find your zoning district using the City’s
Public Interactive Zoning Map
Review the Chico ADU Development Standards to determine the size, placement
and design requirements for your ADU project.
Find your best fit! When it comes to ADU designs, you’ve got two
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.
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