How to Get an ADU Permit in San Bernardino

What Is an ADU?

An Accessory Dwelling Unit (ADU) is a self-contained residential unit located on the same lot as a single-family home. It can be:

Detached (standalone structure),
Attached (connected to the main house),
Or a garage/basement conversion.

To legally construct or convert an ADU, homeowners typically need to obtain an ADU permit, which ensures the unit complies with local zoning, safety, and building regulations. ADUs are an affordable way to expand housing, generate rental income, or provide a home for family members — all without buying a new property.

Key ADU Regulations in San Bernardino County

San Bernardino County follows California state law on ADUs while applying some local building standards. Here’s what you need to know:

Regulation	Details
ADU Size Limits	Up to 850 sq ft for 1-bedroom; 1,000 sq ft for 2+ bedrooms
Setbacks	4 ft side and rear setbacks for detached ADUs
Height Limit	Up to 16 ft (more allowed in some cases)
Lot Zoning	Allowed in most residential zones
Parking Requirements	One space may be needed unless exemptions apply (e.g. near transit)
Owner-Occupancy	Not required until at least 2025
Permitting Timeline	Usually 1–3 months depending on complexity

Steps to Get an ADU Permit in San Bernardino County

Step 1: Determine Eligibility

Confirm your zoning, lot size, and utility access
Use county zoning maps or contact planning department

Step 2: Design Your ADU

Choose type: detached, garage conversion, attached
Hire an architect or designer to draft building plans

Step 3: Submit Your Permit Application

Submit plans via the EZOP online permitting portal
Include site plan, floor plan, elevations, Title 24 energy calcs

Step 4: County Plan Review

Wait for building department feedback
Make revisions if required

Step 5: Permit Approval & Construction

Once approved, you receive permits and begin construction
Schedule inspections throughout the build

Step 6: Final Inspection & Occupancy

Upon completion, the final inspection approves the ADU for occupancy

How Much Does an ADU Permit Cost in San Bernardino County?

Permit Category	Estimated Cost
Building Permit	$1,500 – $3,500
Plan Review & Processing Fees	$500 – $1,200
Mechanical, Electrical, Plumbing	$300 – $800
School Impact Fees	$3–4 per sq ft (only over 750 sq ft)
Fire Dept Review (if required)	$200 – $500
Estimated Total	$2,500 – $6,500+

Benefits of a Permitted ADU in San Bernardino County

Benefit	Why It Matters
✅ Rental Income	Generate steady income from long-term or short-term rentals
🏠 Multi-Generational Living	Keep family members close while maintaining privacy
💰 Increase Property Value	Homes with legal ADUs sell for more
📜 Legal & Insurable	Avoid fines, eviction notices, or forced removal
🔋 Energy Efficient	New ADUs must meet Title 24 energy standards
🔓 Access to Financing	Easier to get loans or refinance with legal status

FAQ

Can I build an ADU on my property in San Bernardino County?

If your lot is zoned residential, and has an existing single-family or multi-family dwelling, you most likely can. Always confirm with your city’s planning division.

How long does the ADU permit process take?

Anywhere from 4–12 weeks depending on your submission quality and the department’s review time.

Do I need a separate address or utilities for the ADU?

Not always. You can share utility connections with the main home, although separate meters are optional and sometimes preferred.

What if I already built an unpermitted ADU?

You may be able to legalize your ADU retroactively, but it will require inspections and plan approval. Contact the building department immediately.

Can I rent out my ADU as an Airbnb?

That depends on your city’s short-term rental laws. Some cities allow short-term rentals; others restrict them or require permits.

Start Your ADU Project with Confidence

Ready to build your legal ADU in San Bernardino County? Don’t navigate the permitting process alone. We help homeowners like you design, permit, and build fully code-compliant ADUs that add value and income to your property.

👉 Schedule Your Free Consultation Today