In addition, a maximum of two (2) detached ADUs are allowed on a lot with an existing multifamily dwelling structure and they may be attached to each other. What is an "Accessory Dwelling Unit"?ADUs are attached or detached residential units that provide complete independent living. Please note that due to Proposition 19, there are new forms available for Change in Ownership Exclusions. Local Forms, Adoption Forms, Family Law Forms, Juvenile Forms, Probate and Court Investigator's Forms, Small Claims Forms, Traffic Forms How does a change in ownership affect property taxes? What constitutes a change in ownership?