Under California's ministerial ADU review process, cities generally can't deny an application on subjective grounds — but they can and do send back applications with corrections needed, which resets part of the 60-day review clock (see our California ADU laws guide for how that timeline works). Most of these correction cycles trace back to the same handful of avoidable issues.
Incomplete plan sets
Missing a required drawing — a plot plan, roof plan, or elevation view, for example — is one of the most common reasons an application bounces back before review even really starts. Cities typically publish a specific checklist of required drawings; missing even one item can trigger a completeness rejection.
Setback or height miscalculations
A design that doesn't actually meet the required setback from property lines, or exceeds the height limit for its zone, gets flagged during plan check. This usually stems from working off outdated zoning information or measuring from the wrong reference point — confirming your specific lot's current standards before finalizing a design avoids this.
Missing structural or engineering detail
Foundation details, structural connections, and load calculations that are too vague or missing entirely are a common source of correction requests, especially for detached new construction where there's no existing structure to reference.
Not accounting for an overlay zone
Properties in a Coastal Zone, Historic District, flood zone, or other overlay often need an additional review step or permit beyond the standard ADU application. Submitting without addressing this upfront generally causes a delay once staff catches it during review.
Utility connection details left unresolved
Plans that don't clearly show how the ADU connects to water, sewer, and electrical service — or that assume a connection type your city doesn't allow — often come back with corrections requested during engineering review.
Application and property records don't match
Discrepancies between the application (owner name, parcel number, existing square footage) and the city's on-file property records can trigger a hold while staff sorts out the mismatch — this comes up more often than you'd expect on older properties with unrecorded additions or ownership changes.
How to submit a clean application the first time
Working with an experienced contractor helps
A contractor who's submitted several ADU applications in your specific city has usually already learned its particular quirks — which reviewer flags which issues, what a complete plan set actually needs to include, and how overlay zones are typically handled. See our guide to comparing contractor bids for how to evaluate this kind of experience when choosing who to work with.
Frequently asked questions
Generally no — state law requires ministerial review, meaning a complete, code-compliant application can't be denied on subjective or discretionary grounds. Corrections and completeness rejections are different from an outright denial, and are usually fixable.
Generally, the clock is tied to a complete application — if corrections are needed, the application isn't considered complete until they're addressed, which affects how the timeline plays out. See our California ADU laws guide for how the 60-day rule works in more detail.
It varies by project and city, but one or two rounds of minor corrections isn't unusual even for a well-prepared application. Repeated rejections over the same issue usually point to something worth addressing directly with your designer or contractor.