Direct answer
The short version
Utility and site surprises can turn a plausible ADU into a much more expensive project. The risk is highest when public data looks clean but panel, trenching, access, drainage, or existing-condition evidence is still missing.
San Jose scope
Where this applies
This is a San Jose-first screening page. Utility providers and site professionals may need to confirm final requirements.
ADUOS checks
What we check first
- Whether utility assumptions are stated as assumptionsModeled
- Whether site access is obviously tightModeled
- Whether existing structures or slope could add frictionModeled
- Whether the case needs photos or a site visitNeeds review
- Whether cost should stay as a wide modeled rangeModeled
What could change this
The answer can move
- Electrical panel evidenceNeeds review
- Utility provider requirementsNeeds review
- Trenching path and accessNeeds review
- Drainage, foundation, slope, or tree conditionsNeeds review
Source notes
Why the label matters
The San Jose FAQ points homeowners to utility-specific confirmation for some requirements. ADUOS should keep utility conclusions Needs review without direct evidence.
FAQ
Common follow-ups
Can public data verify utility cost?
Usually not fully. Public data can flag risk, but utility and site evidence often decides the real cost.
What evidence helps first?
Panel photos, visible access constraints, utility correspondence, and a basic site review help narrow the range.