Module 10 · Lesson 5
Planning vs. Building and Safety: Two Reviews, Two Languages
Your ADU application passes through two different city functions with different rulebooks. Knowing which is which decodes the whole process.
City hall looks like one building from outside. Your application experiences it as (at least) two different departments with different rulebooks — and knowing which is which decodes half the confusing things that happen during permitting.
Planning (also called Zoning). Asks: may this project exist here? Their rulebook is the zoning code and the state ADU law that overrides parts of it — setbacks, height, unit size, parking, lot standards. Everything in Module 5 is Planning's territory. For ADUs, their review is ministerial and usually quick: your project's dimensions and placement either comply or they don't.
Building and Safety. Asks: will this structure be safe and code-compliant? Their rulebook is the California Building Standards Code — structure, egress, fire protection, energy (Title 24), plumbing, mechanical, electrical. Everything in Modules 8–9 that involved the word "code" is theirs. This is the deeper, longer review, and the source of most correction items.
Why the split matters to you, practically:
- Corrections arrive in two dialects. "Reduce height to comply with the certified ordinance" is Planning; "provide hold-down schedule per detail 4/S2" is Building. Your team routes each to the right expert — and when you read the letter, the department tag tells you which conversation is happening.
- They can disagree with each other. Planning approves a placement; Building's fire-access comment nudges the building elsewhere. Coordinated teams anticipate the classic collisions.
- Sequencing varies by city. Some route Planning first, then Building; others review in parallel. Parallel is faster; sequential explains why "we're approved!" (by Planning) can precede months of (Building) plan check. Ask your city which model it uses and set your calendar expectations accordingly.
- State ADU protections bind them differently. Most of Module 5's guarantees constrain Planning — a checker in Building asking for a bigger beam isn't violating the 4-foot setback rule; they're doing a different job. Knowing the lanes keeps everyone's expectations fair.
Key takeaways
- Planning reviews may it exist here (zoning, ADU law); Building & Safety reviews is it safe (building codes).
- Correction letters come in two dialects — the department tag tells you which rulebook is speaking.
- Parallel review is faster than sequential; ask your city which it runs.
- State ADU guarantees mostly bind Planning; Building's code review is a separate, legitimate lane.