If you want a single sentence that explains why most San Diego ADU projects take longer than expected, it's this: the city owns the permit clock, and they won't rush it for you.
But you can dramatically reduce your timeline by understanding what's actually happening.
The real timeline, step by step
For a typical detached ADU in the City of San Diego:
1. Plan preparation (1–2 months) — architectural, structural, Title 24 energy, and MEP drawings. This is your builder's clock, not the city's. 2. Initial submission (1 week) — electronic plan submission through DSD's online portal. You get a plan check number. 3. First review (3–6 weeks) — the city's plan checker issues corrections across building, planning, fire, and utility departments. 4. Corrections round 1 (2–4 weeks) — your architect and builder address comments. 5. Second review (2–4 weeks) — the city reviews corrections. 6. Corrections round 2 (1–3 weeks, if needed) — most projects resolve in rounds 1 or 2. 7. Permit issuance (1 week) — pay fees, pick up permit.
Total: 2.5 to 6 months for most projects. Expect longer on coastal, historic, or fire-severity lots.
Fees by jurisdiction
These are 2026 estimates for a 900 sqft detached ADU. Your actual fees will vary.
- City of San Diego — $14,000 to $22,000 (includes plan check, building permit, school fees, SDG&E, water/sewer)
- Chula Vista — $11,000 to $17,000
- La Mesa — $12,000 to $18,000
- Encinitas — $18,000 to $28,000 (coastal adds)
- Escondido — $9,000 to $14,000
- County of San Diego (unincorporated) — $13,000 to $20,000
The five most common pitfalls
After hundreds of ADU permit submissions, these are the recurring failure modes:
1. Setbacks you didn't know existed
San Diego has state-minimum ADU setbacks (4' side/rear), but overlay zones — coastal, historic, fire — often override them. Always check overlays before committing to a design.
2. Utility capacity
SDG&E transformer capacity, water meter capacity, and sewer lateral capacity are silent killers. A common situation: plans get approved but SDG&E requires a transformer upgrade that adds 4 months and $15K.
3. Fire sprinklers
If your main house has sprinklers, your ADU needs them too. If not, you usually don't — but check, because the cost delta is $8K–$14K.
4. Title 24 energy
California's energy code is updated every three years. The 2025 update requires electric heat pumps for new ADUs. Don't let an architect using a 2022 template slip past this.
5. Historic overlays
Entire blocks of North Park, Mission Hills, and Uptown are under historic review. This doesn't mean you can't build — it means the design needs to be respectful of character. Historic review adds 1–3 months.
How ADU PALS moves faster
We don't promise the city will move faster. We promise that we won't add a day to your timeline.
- Every submission is pre-reviewed against a 180-item SD County checklist.
- Our permit manager has direct relationships with every major reviewer in the city.
- We resolve corrections the week they land, not the month.
The result: our ADUs typically clear permit in ~3.5 months from submission, vs. the 5–6 month average.
Ready to start?
Send us your address. We'll pull the zoning, overlays, and utility status before you spend a dollar on design.
