ADU Rules in Fremont

Fremont permits Accessory Dwelling Units (ADUs) and Junior ADUs (JADUs) on all residentially zoned properties under California state law (Government Code §65852.2) and local ordinance (Fremont Municipal Code Section 18.190.005, Ordinance 06-2023). Fremont stands out for its preapproved plans program offering 7-business-day review.

What You Can Build

Single-Family Lots (R-1-6, R-1-8, R-1-10, R-2)

• One ADU (attached or detached) plus one JADU per lot
• Detached ADU: up to 1,200 square feet
• Attached ADU: up to 50% of primary dwelling or 1,200 sq ft, whichever is less
• JADU: up to 500 square feet within existing structure

Multifamily Lots (R-3 zones)

• Conversion ADUs: Up to 25% of existing units (minimum 1)
• Detached ADUs: Up to 2 new detached ADUs per property

Size Limits

Setbacks

• Front setback: Must comply with base zone (20 ft in R-1-6, 25 ft in R-1-8/R-1-10)
• Side setback: 4 feet for detached ADU
• Rear setback: 4 feet for detached ADU
• Conversion exception: Existing structures maintain current setbacks

Height

• Detached ADU (single-family lot): 16 feet maximum
• Attached ADU: Up to 25 feet
• Near transit: Up to 18 feet for detached ADUs within ½ mile of a BART station or major transit stop
• Multifamily lots: Up to 25 feet

Parking

No additional parking is required for ADUs in Fremont under state law. Garage conversions do not require replacement parking.

Owner Occupancy

• ADUs: Not required (per AB 976)
• JADUs: Owner must occupy either the JADU or primary residence

Preapproved Plans Program

Fremont offers a preapproved ADU plans program with significant advantages:

• 7-business-day review (vs. standard 60-day timeline)
• Flat $1,000 plan review fee
• Plans have already been reviewed for building code compliance
• Multiple floor plan options available

Visit the Fremont ADU page for available preapproved plans.

Permit Process

ADU permits are processed through ministerial review — no public hearing or discretionary approval.

Standard Process

1. Verify zoning: Check your property using the Fremont zoning map
2. Plan preparation: Prepare custom plans or select a preapproved plan
3. Submit application: File with the Community Development Department
4. Plan review: 60-day maximum for custom plans; 7 business days for preapproved plans
5. Permit issuance: Receive building permit and begin construction
6. Inspections: Schedule required inspections during construction
7. Final approval: Certificate of Occupancy upon passing final inspection

Expedited Process (Preapproved Plans)

1. Select from available preapproved plans
2. Submit with site-specific information
3. 7-business-day review
4. Permit issuance and construction

Contact the Planning Division at (510) 494-4440.

Fees and Costs

• ADUs under 750 square feet are exempt from development impact fees
• Preapproved plans: Flat $1,000 plan review fee
• Custom plans: Standard plan check fees based on project scope
• Building permit and inspection fees apply
• Utility connection fees may apply for detached ADUs

Key Considerations

• Fremont has Transit-Oriented Development (TOD) overlay zones near BART stations — ADUs near Warm Springs, Fremont, and Irvington BART stations may qualify for additional height
• Properties in the Hillside (H-I) Overlay are subject to additional grading and development standards
• The Historical Overlay District (HOD) imposes design review for properties in historic areas
• Fremont uses lot-size-based R-1 sub-zones (R-1-6, R-1-8, R-1-10, R-1-20, R-1-40) — verify your exact sub-zone
• Solar panels are required on new detached ADUs per California Energy Code
• Fire sprinklers required only if the primary dwelling has them
• Check FEMA flood maps — some areas near creeks have flood risk

Official Resources

• Fremont ADU Information
• Fremont Municipal Code Section 18.190.005
• Fremont Municipal Code (Title 18 - Zoning)
• Fremont Planning Division
• California Government Code §65852.2