A one-stop source about multigenerational homes, laneway houses, ADUs, granny flats, in-law units, accessory dwelling units…
Rules for creating ADUs vary from place to place. Check the table below for links to your area.
If you’d like to share (or correct) a link for your city or county, please leave a comment below or otherwise contact us! We’d like to have a completely up-to-date list for the entire continent.
|Arizona||Phoenix (called a ‘guesthouse’)|
|California||Lake Elsinore – “second unit”
Los Angeles – defaults to state standards
San Diego (City) – “Companion Unit”
San Diego (County)
San Jose (Section 20.30.150)
|District of Columbia|
|Florida||Jacksonville – not allowed|
|Illinois||Chicago – not allowed|
|Michigan||Detroit – Not allowed except carriage houses built prior to 1940 (p. 461)
|New York||New York City – Not allowed|
|Oregon||Beaverton – section 40.05
Hillsboro – section 88a
Salem – Not allowed
Dallas – only by special exception
|Wisconsin||Madison (p. 28-199)|
Here is Accessory Dwelling Unit Zoning Codes from a range of cities that allow ADUs; the spreadsheet includes summaries of facets of the respective regulations.If you’re willing to add to this dataset for your state, please contact us. Portland, OregonFor more in depth information on Portland’s ADU regulations, review the following information.An introduction to the rules governing ADUs in Portland, OR is contained in this on-line guide. Among its more helpful links are:
Portland also allows accessory structures, some permitted and some not, that don’t qualify as separate dwelling units yet often have attributes similar to ADUs. For a table-format summary of codes related to these other structures, check out this Accessory Structure (Informal) Code Guide.In 2003, Portland reviewed its ADU regulations and came up with recommended program changes to better meet the public policy objectives of the program. This Accessory Dwelling Unit Monitoring Project report contains lots of good information, including case studies and images of built ADUs.