Thinking about adding an Accessory Dwelling Unit (ADU) in Los Angeles in 2025? Whether it’s a rental unit, guest house, or extra space for family, ADUs are one of the best ways to add value and flexibility to your property.
But before you break ground, there’s one thing you can’t ignore: permits. The ADU permit process in Los Angeles can be slow, confusing, and expensive—unless you know what to expect. This guide will walk you through the real 2025 process, local rules, costs, and common mistakes to avoid.
Featured Snippet Answer
To build an ADU in Los Angeles in 2025, you need to submit detailed plans to LADBS, pass plan check, and receive multiple permits including building, electrical, and plumbing. The full process takes 6–12 weeks, depending on complexity.
1. What Is an ADU (and Why Are So Many LA Homeowners Building One)?
An Accessory Dwelling Unit (ADU) is a self-contained home on the same lot as a single-family or multi-family residence. In LA, this includes:
- Garage conversions (attached or detached)
- Stand-alone new construction units
- Attached additions to your home
- Above-garage units
Since California relaxed ADU laws in 2020, more homeowners have jumped on the opportunity to build them for rental income, multigenerational living, or just more space.
Alt-text: Detached backyard ADU under construction in Los Angeles with framing visible
2. What Permits Are Required for an ADU in Los Angeles?
To build a legal ADU in LA, you’ll need approval from the Los Angeles Department of Building and Safety (LADBS) and possibly additional city agencies (planning, fire, utilities).
🚧 Required Permits Typically Include:
- Building permit
- Electrical permit
- Plumbing permit
- Mechanical (HVAC) permit
- Grading or foundation permit (if applicable)
Most ADU plans require plan check, where the city reviews your designs to ensure they meet code.
External Link: Check LADBS ADU Requirements →
3. How Long Does the ADU Permit Process Take?
In 2025, expect timelines like this:
| Step | Timeframe |
|---|---|
| Initial design + engineering | 2–3 weeks |
| LADBS plan check | 4–8 weeks |
| Permit approval | 1–2 weeks |
| Revisions (if needed) | 1–3 weeks |
⏳ Total Time to Permit Approval: 6–12 weeks on average.
Alt-text: Homeowner reviewing ADU site plans with an architect in Los Angeles backyard
4. ADU Permit Costs in Los Angeles
🧾 Breakdown of Common Costs:
- Plan check and permit fees: $3,000–$8,000+
- Impact fees (waived for most ADUs <750 sq ft): $0–$3,000+
- Utility upgrades: $2,000–$10,000+ (depends on panel, gas meter, sewer)
LA waives certain fees for ADUs under 750 sq ft if they meet affordability or owner-occupancy requirements.
5. Common Mistakes That Delay or Deny Your ADU Permit
❌ Mistakes We See Weekly:
- Submitting incomplete plans
- Trying to convert a garage without proper setbacks or fire separation
- Not disclosing lot issues (easements, utilities)
- Using unlicensed designers or contractors
- Ignoring LADWP rules for power, water, and sewer
✔️ Solution: Work with a design-build contractor who handles all architectural, engineering, and LADBS coordination for you. It saves time and prevents red tape delays.
“We tried doing the ADU permit ourselves and wasted 3 months going back and forth. Once we hired Buildwright, they got approvals in 6 weeks flat.”
— Luis R., Highland Park
6. Los Angeles ADU Rules You Need to Know in 2025
🏡 Quick Snapshot:
- Max ADU size: Up to 1,200 sq ft (depends on lot + zoning)
- Setbacks: 4 ft from rear and side property lines
- Parking: Not required if within ½ mile of transit
- Lot coverage: Must meet zoning code (R1, R2, RD, etc.)
- Owner-occupancy: No longer required for most ADUs
📌 Bonus: If you build an ADU and a JADU (Junior ADU), you can legally have 3 dwelling units on a single-family lot.
FAQ: LA Homeowners Ask About ADU Permits
Q: Do I need an architect for an ADU?
A: Not legally, but most projects require engineered drawings. A design-build firm usually includes this service.
Q: Can I convert my garage into an ADU?
A: Yes—if it meets fire, setback, and utility requirements. You’ll need permits and plan check.
Q: What if my permit gets denied?
A: LADBS will issue corrections. A good contractor or expeditor can revise and resubmit on your behalf.
Q: Can I rent out my ADU in LA?
A: Yes. Long-term rentals (30+ days) are legal. Short-term rentals may require additional registration.
Ready to Start Your ADU Without the Headaches?
Permitting an ADU in LA is doable—you just need the right team and the right process.
We’ve helped dozens of homeowners across Los Angeles get permit-ready plans approved the first time around.
👉 DM us “QUOTE” on Instagram to book a free 15-minute consult about your property.
Or contact us here and we’ll walk you through your options.
Conclusion: Start Smart, Build Fast
Building an ADU is one of the smartest moves you can make as a Los Angeles homeowner—but only if you start with a solid plan and get your permits right the first time.
Use this guide as your blueprint, avoid the common mistakes, and when you’re ready, we’re here to help you turn your ADU vision into reality.
