Yuna Drafting
Your ADU permit set requirements in San Jose are non-negotiable: site plan, floor plans, elevations, building sections, foundation plan, roof framing plan, and a Title 24 energy report are all required before the Building Division opens your file for review. Understanding the full scope of what goes into a residential permit set for Santa Clara County before you draft a single line is the difference between a clean approval and a stack of correction notices.
ADUs are one of the most active permit categories in the Bay Area right now, and San Jose's Building Division processes hundreds of ADU applications every quarter. The City has made genuine strides toward a more predictable review process — but predictable doesn't mean effortless. Plan check still expects thorough documentation, precise code callouts, and tight coordination between your architectural, structural, and energy drawings.
Whether you're working on a detached backyard unit, a garage conversion ADU, or a junior ADU carved out of existing living space, this guide covers exactly what your permit set needs, where most applicants stumble, and how to build a package that moves efficiently through plan check. If you want a professional team handling the full submission, our permit set services are designed specifically for Bay Area ADU projects.
Contents
- What Most ADU Applicants Get Wrong About the Permit Package
- How to Build a Compliant ADU Permit Set Step by Step
- Insider Tips for Getting Through San Jose Plan Check Faster
- Detached ADU vs. Garage Conversion: How the Permit Sets Differ
- Planning Your ADU Permit Set for Long-Term Code Compliance
- Quick Wins That Move Your ADU Application Forward Today
- Frequently Asked Questions
- Key Takeaways
What Most ADU Applicants Get Wrong About the Permit Package
The "Simple ADU" Myth
The most expensive assumption you can make is that a small ADU demands a simple permit set. San Jose's Building Division applies the full California ADU standards from the Department of Housing and Community Development regardless of unit size, which means a 400-square-foot studio gets the same sheet count as a 1,200-square-foot detached two-bedroom. Plan reviewers are not going to approve a sketched floor plan and a basic site diagram — they need a complete, stamped, code-referenced permit set every single time.
- Missing a single required sheet triggers a correction notice and restarts your review clock
- Incomplete Title 24 energy calculations are the top reason ADU permit sets fail first review in San Jose
- Skipping a roof framing plan on a detached ADU is a guaranteed correction, even for simple gable roofs
- Omitting a window and door schedule forces the reviewer to request it before they can confirm egress compliance
One Set Does Not Cover Every Jurisdiction
Santa Clara County's unincorporated areas, San Jose, Sunnyvale, and Campbell all maintain distinct plan check checklists even though they draw from the same California Building Code. What satisfies a San Jose reviewer won't automatically pass a Santa Clara County Building Inspection counter submittal. Always pull the current jurisdiction-specific checklist and map every line item to a sheet in your set before you upload a single PDF.
How to Build a Compliant ADU Permit Set Step by Step
Start with the Site Plan and Zoning Compliance
Your site plan is the foundation of the entire permit set, and plan check reviewers open it first to confirm zoning eligibility before they look at anything else. Here's what San Jose requires on every ADU site plan:
- Property lines with dimensions and north arrow at a recognized engineer's scale
- All existing and proposed structures with dimensions and setbacks called out to property lines
- Driveway, walkways, and accessible route to the ADU entrance
- Utility connection points — sewer lateral, water service, and electrical panel location
- Tree locations if any protected trees fall within the project footprint or drip line
- Impervious surface calculations if your jurisdiction triggers stormwater review
Pro tip: Pull your parcel data directly from Santa Clara County's GIS portal to verify property line dimensions before you finalize the site plan — discrepancies between GIS data and your deed description will trigger a correction every time.
Structural and Energy Documentation
After the site plan locks in zoning compliance, you build the architectural core — floor plans, elevations, and sections — then layer in structural and energy documentation on top. Title 24 energy calculations are mandatory for all new ADUs in California, and the CF1R report must be generated by a certified energy analyst and bound into your submittal package before the portal will accept the file. Your structural drawings must trace the full lateral and gravity load path from roof to foundation, with every connection detailed and cross-referenced to your structural general notes.
- Floor plans: fully dimensioned, with room labels, window and door schedule, and accessibility path noted
- Elevations: all four sides, with finish materials, height dimensions, and grade line shown
- Building sections: minimum two perpendicular cuts through the ADU showing floor-to-roof assembly
- Foundation plan: footing sizes, post pad locations, and hold-down hardware called out by manufacturer model
- Roof framing plan: rafter or truss layout with ridge beam sizing and all special connections detailed
Insider Tips for Getting Through San Jose Plan Check Faster
Annotate Directly to the Code Section
Reviewers are working through dozens of permit sets simultaneously, and the fastest sets to approve are the ones where every code requirement is already cited on the drawing itself. Don't assume the reviewer knows you're meeting egress requirements — call out "CBC Section 1030" next to your emergency escape window on the floor plan. Every annotation that references a code section saves the reviewer a lookup and saves you a correction cycle, so treat your drawings like a self-contained compliance argument.
- Note CBC, CRC, CMC, CPC, and CEC references on the sheet where each system is shown
- Call out ADU-specific exemptions explicitly — fire sprinkler exemptions under SB 13 where applicable, for instance
- Use a general notes sheet to consolidate code edition references, special inspection requirements, and geotechnical report citations
Use the Pre-Application Consultation
San Jose's Development Services team offers pre-application meetings for ADU projects, and using that meeting strategically is one of the highest-leverage moves you can make before finalizing your permit set. Bring a draft site plan and preliminary floor plans, ask specifically about any site-specific constraints — hillside overlays, flood zones, heritage tree setbacks — and document the responses in writing. A single targeted pre-application meeting can eliminate two or three correction cycles that would otherwise cost you weeks of review time and resubmittal fees.
Detached ADU vs. Garage Conversion: How the Permit Sets Differ
Sheet-by-Sheet Comparison
The sheet requirements shift meaningfully between a ground-up detached ADU and a garage conversion ADU, because the conversion modifies an existing structure rather than building new from scratch. Here's how the two permit packages compare side by side:
| Sheet / Document | Detached ADU (New Construction) | Garage Conversion ADU |
|---|---|---|
| Site Plan | Required — show new footprint and setbacks | Required — show existing garage, new use noted |
| Floor Plans | Fully dimensioned new construction | Existing conditions + proposed overlay |
| Elevations | All four sides, new materials called out | All four sides, changes from existing noted |
| Foundation Plan | Full new foundation design required | Existing footing verification + any new piers |
| Roof Framing Plan | Always required | Required if roof is altered; may waive if unchanged |
| Title 24 CF1R Report | Full new-construction compliance pathway | Addition/alteration compliance pathway |
| Structural Engineer Stamp | Required for two-story or non-standard framing | Often required — existing lateral system must be evaluated |
| Soils/Geotechnical Report | Required if over 1,200 sq ft or on hillside parcels | Typically not required for standard conversions |
When a Structural Engineer Stamp Is Required
San Jose requires a licensed structural engineer's stamp on ADU drawings more often than most homeowners expect, and the triggers go beyond what's obvious at first glance. Review whether your ADU in San Jose needs a structural engineer stamp before you lock in your drafter scope, because adding engineering after the fact typically delays your submission by two to four weeks. The clearest triggers for mandatory engineering include any two-story ADU, any garage conversion where the existing lateral system is inadequate for the new occupancy loads, and any new foundation bearing on expansive or liquefiable soils per a geotechnical report.
Planning Your ADU Permit Set for Long-Term Code Compliance
Future-Proofing with Accessible Design
California law does not currently require ADUs to meet full ADA accessibility standards, but designing for visitability — a zero-threshold entry, 32-inch clear door widths, and a ground-floor bathroom with blocking for future grab bars — adds minimal cost at the drafting stage and significant resale flexibility down the road. Documenting these features explicitly in your permit set signals intentionality to reviewers and positions your unit well if accessibility requirements expand in future California code cycles.
- Note zero-threshold entry conditions on the door schedule and in the floor plan notes
- Call out 36-inch hallway clearances where provided in the dimensioned floor plan
- Show grab bar blocking in the bathroom framing details even if bars aren't installed at permit closeout
Maintaining Your Permit Record
Once your ADU permit closes, store the stamped approved set, all plan check correction letters, and the final inspection card together in a permanent project file. Future buyers, lenders, and refinance appraisers will ask for documentation, and a complete permit record removes any ambiguity about the unit's legal status. If you ever pursue a remodel or expansion, your drafter can use the approved set as a verified as-built baseline rather than re-measuring the entire unit from scratch and rebuilding the drawing set.
Quick Wins That Move Your ADU Application Forward Today
Pre-Submission Checklist
Before you submit your permit set to San Jose's online permit portal, run through this checklist — catching these items now saves you a minimum two-week correction cycle and the associated resubmittal fee:
- Confirm your parcel is zoned for the ADU type you're proposing — detached, attached, or JADU
- Verify setbacks comply with current San Jose ADU ordinance minimums — four feet rear and four feet side for detached units
- Confirm your sheet count matches the jurisdiction checklist item for item, with no gaps
- Check that your Title 24 CF1R report reflects the final design, not a preliminary energy model run
- Verify that all sheets are consistently dated and that your sheet index matches the actual sheets in the uploaded PDF
Floor Plan Layout Strategy
Efficient floor plan layouts do more than satisfy code — they also accelerate plan check because reviewers can instantly confirm egress, natural light, and accessible path without hunting through the drawing for information. Study ADU floor plan layouts that pass Santa Clara County plan check to understand which configurations move fastest through review and which ones consistently draw the most correction questions. Keeping your floor plan clear, fully dimensioned, and logically organized is one of the simplest and highest-impact things you can do to shorten your overall approval timeline.
Frequently Asked Questions
San Jose requires a site plan, dimensioned floor plans, all four building elevations, at least two building sections, a foundation plan, a roof framing plan, a window and door schedule, and a Title 24 CF1R energy report at minimum. Structural drawings are added when engineering is triggered by the project scope.
Yes. California's Title 24 energy standards apply to all newly constructed ADUs and to garage conversions that change the conditioned space, regardless of unit size. The CF1R compliance report must be generated by a certified HERS rater or energy analyst and included in your permit submittal package.
Standard over-the-counter ADU plan check in San Jose typically runs two to four weeks for a first review cycle when the submittal is complete. Correction cycles add two to three weeks each, which is why submitting a clean, fully documented permit set from the start is so critical to your overall timeline.
San Jose's ADU ordinance requires a minimum four-foot rear setback and a minimum four-foot side setback for detached ADUs. ADUs that replace an existing legally constructed accessory structure in the same footprint may qualify for reduced or no setback requirements under state ADU law.
In most cases, yes. A garage conversion changes the occupancy and often requires shear wall upgrades, new lateral bracing, and foundation modifications that trigger engineering review. Your drafter should scope the structural needs early so engineering coordination doesn't delay your submittal.
A JADU permit set is generally simpler than a detached ADU set because the unit is carved out of existing living space, but it still requires a site plan, floor plan showing the JADU boundaries, an efficiency kitchen detail, a separate entrance detail, and Title 24 documentation for any new mechanical or envelope work.
Incomplete or mismatched Title 24 energy documentation is the leading cause of first-cycle corrections on ADU permit sets in San Jose. The second most common issue is a site plan that doesn't accurately reflect setback dimensions or doesn't show all existing structures on the parcel — both of which force reviewers to issue corrections before they can assess zoning compliance.
Key Takeaways
- ADU permit set requirements in San Jose are fixed regardless of unit size — every project needs a site plan, full architectural drawings, structural documentation where triggered, and a certified Title 24 energy report.
- Jurisdiction-specific checklists vary across Santa Clara County, so always pull the current checklist for your exact permit authority and map every line item to a sheet before you submit.
- Garage conversion ADUs almost always require a structural engineer stamp because the existing lateral system must be evaluated for the new occupancy, and scoping that engineering work early prevents costly delays.
- A clean, annotation-rich, fully documented permit set submitted the first time is the single most effective strategy for minimizing correction cycles and moving your ADU through plan check on schedule.
