Building an ADU (Accessory Dwelling Unit) in San Diego sounds exciting. Extra income, more living space, a flexible property investment. But before any of that happens, you need a permit from the City of San Diego. And that’s where most homeowners stop, take a deep sigh, and ask the big question—How long does it really take to get an ADU permit in San Diego?
The short answer: usually 6 to 12 months. But that’s only the range. Your own timeline can swing shorter or longer depending on planning, paperwork, design, city review workload, and how you respond to corrections.
This guide breaks everything down so you know where time gets lost, where you can gain it back, and what strategies shrink the waiting period.
Why the ADU Permit Timeline Matters
Every week of permit delay equals another week when your project can’t move forward. For professionals and homeowners alike, time wasted in the permit cycle is money tied up in land, design fees, and missed rental income.
Waiting six months or more can feel frustrating. But knowing why it takes that long helps set realistic expectations. More importantly, it shows you exactly where you have leverage.
Average ADU Permit Timeline in San Diego
The average ADU permit timeline in San Diego falls into these ranges:
- Simple ADUs using pre-approved plans: 3–6 months
- Custom ADUs or conversions with minimal site issues: 6–9 months
- Complex builds, duplex lots, or hillside sites: 9–12 months
City processes are improving, but the law still requires multiple checks. Building, zoning, fire, drainage, and parking all get reviewed. If even one area comes back with corrections, those corrections can stretch the timeline by weeks.
Step 1: Pre-Application Research (1–4 Weeks)
Before you submit anything, you’ll spend time gathering information. Key tasks in this phase:
- Checking zoning and land use rules for your property
- Reviewing parking requirements
- Scheduling a design consultation
- Ordering surveys or site measurements
Some homeowners skip this prep and pay for it later. Missing zoning data usually means resubmittals. That alone can cost months.
Step 2: Design & Drafting (4–12 Weeks)
The design phase is sneaky. It looks fast if you only count the time spent drawing plans—but revisions usually stretch this stage.
- Using pre-approved ADU plans? You could lock this down in about a month.
- Going custom? Expect at least 8 to 10 weeks between concept and final drawings.
Homeowners who change their minds mid-design almost always tack on extra time.
Step 3: Submitting to the City (1–2 Weeks)
Once your plans are ready, they go into the city’s online portal. Submitting is quick. The wait starts after you hit “submit.”
A small detail—if your submission packet is incomplete, it gets rejected. That resets the clock. Clean applications move forward. Messy applications go back to the starting line.
Step 4: City Review Cycle (8–16 Weeks)
The review period is the long middle stretch. During review, several departments check your application:
- Zoning and planning
- Building safety
- Fire department
- Engineering (drainage, utilities)
- Parking compliance
If everything checks out right away, your permit clears in one cycle. If not, you’ll receive corrections. That’s where delays add up.
Step 5: Corrections and Resubmittals (Varies: 4–12 Weeks)
Corrections are common. It’s not a failure—it’s how the system works. Most ADU projects get corrections at least once.
The timeline depends on:
- How fast you respond. Some owners turn corrections around in days. Others leave them sitting for months.
- How complex the corrections are. Simple labeling changes? Days. Redesigning a parking solution? Weeks.
The faster you reply and resubmit, the faster your file gets back into the review cycle.
Step 6: Final Approval (1–3 Weeks)
After corrections are cleared, the final review moves quickly. At this stage, it’s about issuing documents and city sign-off.
Total Timeframe Recap
- Pre-Application: 1–4 weeks
- Design & Drafting: 4–12 weeks
- Submission: 1–2 weeks
- Review: 8–16 weeks
- Corrections: 4–12 weeks
- Approval: 1–3 weeks
Grand total: about 6–12 months in most cases.
Factors That Affect Your Timeline
Not every ADU permit runs the same. Common factors create speed-ups or slowdowns.
Pre-Approved vs Custom Plans
Pre-approved plans shave off months. They skip the design corrections stage.
Property Conditions
Corner lots or hillside properties trigger extra checks. That extends timelines.
Applicant Responsiveness
Your speed in returning corrections is the most underrated factor.
City Workload
Sometimes the queue is simply long. High-volume months stretch reviews.
Can You Speed It Up?
Yes. While you can’t eliminate city reviews, you can avoid what homeowners often do to slow themselves down:
- Submitting incomplete applications
- Picking designers unfamiliar with San Diego codes
- Delaying responses to correction letters
- Ignoring parking calculations
- Overcomplicating design features
Trim those issues, and you immediately move faster.
Tips to Cut Weeks Off Your Permit Timeline
- Use a pre-approved ADU plan if possible
- Hire designers and contractors who’ve worked with San Diego ADUs before
- Double-check every form before submission
- Stay on top of communication with the city
- Treat correction responses like deadlines, not suggestions
Common Myths About Permit Timelines
Myth 1: Hiring professionals guarantees faster permits.
Reality: They reduce mistakes but can’t control city workloads.
Myth 2: Small ADUs take no time.
Reality: Smaller in size doesn’t always mean shorter in process.
Myth 3: The city is against ADUs.
Reality: San Diego wants more housing but is bound by review laws.
What Happens If Your Permit Gets Stuck?
Sometimes permits seem frozen. In that case:
1. Call the reviewer directly.
2. Request a project status update through the portal.
3. Escalate to a supervisor if no movement happens beyond reasonable timeframes.
This isn’t about being pushy—it’s about keeping attention on your project.
FAQs About ADU Permit Timing
Q: Can an ADU permit take less than 6 months?
A: Yes, with pre-approved plans and fast corrections.
Q: What’s the longest it could take?
A: More than a year for complex properties or unresponsive applicants.
Q: Do accessory structures like garage conversions move faster?
A: Often yes, since the structure already exists. But corrections can still add months.
Final Thoughts
Getting an ADU permit in San Diego isn’t fast. But it doesn’t have to drag on forever. On average, count on 6–12 months, with pre-approved plans landing on the shorter side and complex custom builds stretching toward the longer side.
The process has clear stages. Each stage offers choices that either cost weeks or save weeks. The best approach is proactive—submit accurately, work with experienced professionals, and stay on top of communication.
Time is money, and in the ADU world, time is rental income. The faster you complete the permit cycle, the sooner you can start building, renting, or using your space.
