How Long Does It Take to Build an ADU in San Diego? (2026 Timeline)
One of the most common questions homeowners ask is:
“How long does it take to build an ADU in San Diego?”
While recent California laws have streamlined approvals, building an ADU still requires careful planning, permitting, and construction. In most cases, San Diego ADU projects take about 12–18 months from initial planning to completion.
Below is a realistic timeline based on typical projects.
1. Feasibility & Property Evaluation
Timeline: 2–6 weeks
The first step is determining what your property can support.
This stage typically includes:
Zoning and ADU eligibility review
Lot layout and setback analysis
Utility access evaluation
Initial budget discussion
A proper feasibility study helps prevent costly redesigns later
2. ADU Design & Architectural Plans
Timeline: 1–3 months
Once feasibility is confirmed, the design phase begins.
This includes:
Floor plan development
Architectural drawings
Structural engineering
Energy compliance documentation
Site plans for permitting
A thoughtful design phase helps ensure the ADU fits both the property and long-term goals.
3. Permitting with the City of San Diego
Timeline: 3–5 months
Plans are then submitted for city review.
During permitting, the city checks for compliance with:
zoning regulations
building codes
fire safety requirements
energy standards
Most projects go through at least one round of plan check corrections before final approval.
Recent state laws, such as SB 543, require cities to determine whether an ADU application is complete within 15 business days, helping reduce early delays.
4. ADU Construction
Timeline: 5–8 months
Once permits are issued, construction begins.
Major construction stages include:
Site preparation and foundation
Framing and roofing
Plumbing, electrical, and HVAC installation
Interior finishes and inspections
Detached ADUs in San Diego typically take five to eight months to build, depending on size and complexity
Total ADU Timeline in San Diego
Most projects follow this general schedule:
Phase Timeline
Feasibility 2–6 weeks
Design1–3 months
Permitting3–5 months
Construction5–8 months
Typical total timeline:
➡ Approximately 12–18 months
Some projects may take longer depending on site conditions, utility upgrades, or design revisions
FAQs: San Diego ADU Timeline
What is the fastest an ADU can be built in San Diego?
In ideal conditions, some projects may finish in about 10–12 months, but most take 12–18 months.
How long does ADU permitting take in San Diego?
Permit approval typically takes 3–5 months, depending on plan review corrections.
Does ADU size affect the timeline?
Yes. Larger detached ADUs or complex sites can add time to both design and construction.
Thinking About Building an ADU?
ADUs remain one of the most powerful ways San Diego homeowners can add housing, generate rental income, and increase property value.
If you’re exploring an ADU project, ADU PALS specializes in designing, permitting, and building ADUs throughout San Diego.
Contact ADU PALS now for free consultation!
