Three legitimate paths to ADU plans
In California, every permitted ADU starts with stamped, code-compliant plans. You have three real options.
1. Pre-approved city plan catalogs
LA, Pasadena, Anaheim, San Diego, Long Beach, and dozens of other cities publish pre-approved ADU plan libraries. Permitting takes 2–6 weeks instead of 8–14, and design fees are slashed.
2. Pre-approved third-party plan sets
Architects and modular makers publish stock plans approved through state-level review. Useful in cities without their own catalog.
3. Custom architect-led design
For unusual lots, hillside sites, or strong design preferences, a licensed architect produces stamped plans, which requires a property-specific written estimate and 4–8 weeks.
What every ADU plan set must include
- Site plan with setbacks, utility paths, and grading
- Floor plan(s) with room dimensions
- Elevations (all four sides)
- Foundation and structural plans
- Title 24 energy compliance
- Mechanical/electrical/plumbing drawings
- Solar PV plan (new detached units)
How to choose
If your city has a pre-approved catalog and one of those designs fits your lot, use it. If you need any customization beyond paint color and finishes, go custom. Hybrid options exist — Vision ADU adapts pre-approved plans for site-specific conditions when possible.
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We design and build across 110+ cities in LA, OC, and the Inland Empire. Book a free site evaluation and we will recommend the right plan path for your lot.
Frequently Asked Questions
Where can I find free ADU plans in California?
Most major cities (LA, San Diego, Pasadena, Anaheim) offer free pre-approved ADU plan downloads on their city websites.
Do I need an architect for an ADU?
Not always. Pre-approved plans bypass full architect involvement. Custom designs do require a licensed architect or engineer.
How long does ADU design take?
2–4 weeks for pre-approved plan selection and site adaptation. 4–8 weeks for custom design.
Can I modify a pre-approved plan?
Minor modifications (finishes, fixtures) yes; layout changes typically require full plan check.
Who owns the plans I buy?
Architects retain copyright. You receive a license to build one ADU from the plans — not the right to reuse them on other lots.
Related Vision ADU Resources
- SB 9 vs ADU in California: Which Path Is Right for Your Property? (2026)
- AB 1033 ADU Condo Conversion in California: Selling Your ADU Separately (2026)
- Detached vs Attached ADU: Which Is Right for Your Property? (California 2026)
- JADU vs ADU in California: Cost, Rules & When to Choose Each (2026)
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- Inland Empire ADU Builder
- 2026 ADU Cost Calculator
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