Module 10 · Lesson 2
What Is Plan Check?
Plan check is the city verifying your plans meet code — on paper, before construction. What reviewers check and what they can't demand.
Plan check is exactly what it sounds like: city staff (or contracted reviewers) go through your plan set line by line, verifying that the proposed building complies with every applicable code — before anything gets built. It's quality control on paper, where fixes cost redlines instead of demolition.
What the checker verifies, sheet by sheet:
- Zoning/planning items: setbacks against your site plan, height against your elevations, size against your floor plans, parking (or its exemptions) — Module 5's rules, applied to your drawings
- Structural: the engineer's calculations and details — do the numbers work, are the seismic elements complete
- Life-safety: egress windows (lesson 8.4), smoke/CO detectors, fire separations, emergency access
- Energy: the Title 24 report matches the actual windows, insulation, and equipment drawn
- Plumbing, mechanical, electrical: fixture counts, venting, panel schedules, that load calc from Module 7
- Consistency: and always, everywhere — do the sheets agree with each other (lesson 9.7's warning made real)
What plan check is NOT. It's not a design critique — ministerial review (Module 5.1) means the checker verifies objective compliance, not taste. No one may reject your ADU for being boxy, modern, or rentable. If a correction ever reads like an opinion, lesson 10.7 is your friend.
Who checks: many cities route ADU sets to in-house checkers; busy ones contract outside plan-check firms; and some let applicants hire approved private checkers to speed things up — worth asking about when timelines matter (recent state law has expanded these options).
How to think about the checker: not an adversary — a proofreader with authority. Checkers catch real mistakes that would have cost real money in the field (an undersized beam, a missing egress). The frustrating corrections are the ambiguous ones, and the next lesson sorts those. But a clean, coordinated set gives a checker very little to write — and that's the strategy: make the easy path for the checker the fast path for you.
Key takeaways
- Plan check verifies objective code compliance on paper — zoning, structure, life-safety, energy, MEP, and inter-sheet consistency.
- It's ministerial: taste and opinion are out of bounds; only objective standards count.
- Some cities allow private or expedited plan check — ask when speed matters.
- The checker is a proofreader with authority; give them nothing to find.