Cupertino, CA Accessory Structures: ADU Rental Restrictions (2026)

020 treats an ADU like any other dwelling for rental purposes with one hard limit: an ADU, including a Junior Accessory Dwelling Unit, may not be used as a rental for a term less than 30 days. The same sentence lets an owner rent the ADU to a tenant different from whoever lives in the main house, which is what makes an ADU a genuine income option in Cupertino rather than a unit that must stay with the same household. The trade-off is on the ownership side: an ADU may not be sold or otherwise conveyed separately from the other dwellings on the lot, so a homeowner cannot subdivide title and sell the ADU as a standalone unit.

State law carves out one narrow path around that ban, at Government Code Sections 66340 through 66342, which allows qualifying nonprofit and public-agency programs to convey ADUs separately under specific affordability terms; outside that program, the local no-separate-sale rule controls. Because the 30-day floor sits inside the zoning chapter rather than the business-license code, the City enforces it as a land-use matter: a property owner who lists an ADU nightly on a short-term rental platform is running an unpermitted use of the parcel, not just skipping a lodging-tax filing.