When comparing pre-approved ADU plans, homeowners often assume that each listing is simple: one plan, one city, one approval status. In reality, public ADU plan data can be more complicated.

A plan may originate in one city or county catalog and appear as accepted in another location. A provider may have one plan that is listed in several jurisdictions. A city may accept plans that started in a county program. If the records are not organized clearly, homeowners can become confused about what the plan is, where it came from, and where it can be used.

That is why it is helpful to understand the difference between an origin ADU plan and an accepted ADU plan listing.

ADU Plan Finder is built around this distinction.…