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.
Please remember this is a volunteer-driven site! If you don’t see your city, or the link for your city is wrong, please let us know with a comment below — or even better, do some digging and leave the correct info in your comment. With your help, we can build an 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)|
More details about Oregon cities
If the table above isn’t enough info for you, here is an older table that focuses on Oregon cities, and has some more details about specific regulations: Accessory Dwelling Unit Zoning Codes .
If you’re willing to add to this dataset for your state, please contact us.
Even more details about Portland, Oregon
For 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.