Direct answer
The short version
Setbacks are the required distances between a structure and property lines or other regulated areas. For ADUs, the practical question is whether your lot has enough usable space after the setback rules and parcel geometry are applied.
San Jose scope
Where this applies
San Jose setback screening should use San Jose rules and your actual parcel geometry. This page does not replace the city checklist or a plan review.
ADUOS checks
What we check first
- Which parcel edge appears to be the front lot lineModeled
- Whether side and rear areas leave plausible ADU spaceModeled
- Whether existing structures reduce usable areaModeled
- Whether the buildable envelope should stay Modeled or Needs reviewModeled
- Whether a survey or city review is needed before trust increasesNeeds review
What could change this
The answer can move
- A different front lot line interpretationNeeds review
- Survey-grade boundary dataNeeds review
- Existing structures not shown in public dataNeeds review
- Special site constraints or overlaysNeeds review
Source notes
Why the label matters
ADUOS does not silently turn a setback calculation into certainty. The buildable envelope stays Modeled when it depends on geometry and assumptions.
FAQ
Common follow-ups
Why does the front lot line matter?
The front lot line affects where the front-yard rules apply. A wrong front-line read can make an ADU look more buildable than it really is.
Is a modeled setback screen enough to build?
No. It is a screening tool. Close calls should be reviewed with better parcel evidence and the city process.