Guide
What homeowners need to know.
Site-specific beats generic
A generic ADU plan can inspire the design, but permit review needs the ADU placed on a real property with setbacks, utilities, access, drainage, and constraints.
Plan sets need coordination
Expect floor plans, elevations, site plan, structural notes, Title 24/energy documentation, utility plans, and city-specific forms when applicable.
Corrections are normal
City comments are not failure. The problem is having no one responsible for answering them.
Cost table
Use ranges until scope is real.
| Item | Planning range | Why it moves |
|---|---|---|
| Basic planning package | $8k-$18k+ | Useful for feasibility and early direction, not always full permit submission. |
| Permit-ready plan set | $15k-$45k+ | Varies by engineering, survey, energy docs, city requirements, and revisions. |
| Preapproved plan adaptation | Variable | Still needs site-specific work and owner/provider coordination. |
Mistakes
Avoid these expensive shortcuts.
- Buying a plan that cannot fit the lot.
- Ignoring utility and foundation assumptions.
- Not asking who handles city corrections.
- Calling something permit-ready when it is really a concept sketch.
FAQ
Fast answers.
Are online ADU plans permit-ready?
Not by default. They still need site-specific placement, code review, utilities, structural/energy coordination, and city forms.
Sources