Fremont's Accessory Structures: The Rules That Matter

Every city handles accessory structures a little differently. In Fremont, California, there are 9 distinct rules that residents and property owners should be aware of. Some are stricter than what neighboring cities enforce, and others are more relaxed. Here is what you need to know.

Tiny Homes

Fremont allows tiny homes as ADUs if built to California Residential Code on a foundation. Tiny homes on wheels are regulated as RVs and generally cannot be primary dwellings.

Key details: Fixed Tiny Home: ADU if CRC-compliant. Minimum Size: 150 sq ft. Foundation: Required for ADU. THOW (RV): Cannot be primary dwelling. Manufactured Home: Allowed with HUD certification.

Contact your local code enforcement office for specific penalty information.

Carport Rules

Carports are allowed as accessory structures in Fremont with a building permit. Front-yard carports face design review. Setbacks and height limits apply.

Key details: Permit Threshold: Over 120 sq ft. Setbacks: Match primary structure. Front Yard: Design review. Height: 12 ft eave. Solar Carports: Expedited review.

Contact your local code enforcement office for specific penalty information.

ADU Permits

Fremont processes ADU permits ministerially under Fremont Municipal Code 18.190.005 (effective August 11, 2023) and California Government Code 65852.2. Applications are filed through the Community Development Department / Planning and Building Permit Services. State law requires the city to act within 60 days of a complete application.

Key details: Code Section: FMC 18.190.005. Review Type: Ministerial (no hearing). Decision Window: 60 days from complete app. Allowed Units: 1 ADU + 1 JADU per SFR lot. Effective Date: August 11, 2023.

Building an ADU without permits violates FMC Title 18 (Zoning) and FMC Title 15 (Building Code). Fremont Code Enforcement can issue stop-work orders, administrative citations (typically $100 first violation, escalating), and double permit fees on application to legalize. Unpermitted ADUs can block sale or refinancing and may trigger an order to remove the structure.

ADU Owner Occupancy

Under FMC 18.190.005 and California Government Code 65852.2(a)(8), Fremont does NOT require owner-occupancy for standard ADUs permitted between January 1, 2020 and December 31, 2024. Owner-occupancy is required only for Junior ADUs (JADUs) under Gov. Code 65852.22, with a recorded deed restriction.

Key details: Standard ADU: No owner-occupancy required. JADU Rule: Owner must live in primary OR JADU. State Authority: Gov. Code 65852.2(a)(8); 65852.22. JADU Deed Restriction: Recorded with Alameda County. Occupancy Limit: Same as single-family home.

Failing to record the JADU deed restriction blocks issuance of the Certificate of Occupancy. Violating the JADU owner-occupancy requirement is enforced through deed-restriction enforcement and Fremont Code Enforcement administrative citations under FMC Title 1. Fremont can also seek injunctive relief and revocation of the Certificate of Occupancy.

If you are coming from a city with tighter rules, you will find Fremont gives residents more flexibility on adu owner occupancy.

ADU Impact Fees

Under California Government Code 65852.2(f)(3) and FMC 18.190.005, Fremont ADUs under 750 square feet are exempt from all city impact fees. ADUs 750 square feet or larger pay impact fees proportional to the primary dwelling's size. Standard building permit and plan-check fees still apply at any size.

Key details: Authority: Gov. Code 65852.2(f)(3). Sub-750 sq ft ADU: Exempt from all city impact fees. 750+ sq ft ADU: Proportional impact fees. Permit/Plan Check: ~$4,000-$9,000 (any size). School Fees: Waived under 750 sq ft.

Fremont cannot legally charge city impact fees on a sub-750 sq ft ADU. If charged in error, the homeowner may demand a refund through the Finance Department or seek a writ of mandate under California Code of Civil Procedure 1085. School facility fees collected by FUSD on a sub-750 sq ft unit are similarly subject to refund under SB 13 / Gov. Code 65852.2.

The rules around adu impact fees in Fremont lean permissive, but that does not mean anything goes.

ADU Rental Restrictions

Fremont prohibits short-term rentals (under 30 days) of any ADU under California Government Code 65852.2(a)(6) and FMC 18.190.005. Long-term rentals (30+ days) of an ADU are allowed but are subject to AB 1482 (Cal. Civ. Code 1946.2) just-cause eviction and statewide rent caps. Fremont does not have a local rent-control ordinance.

Key details: Min Rental Term: 30 days (Gov. Code 65852.2(a)(6)). ADU as STR: Prohibited (not primary residence). AB 1482 Cap: 5% + CPI / max 10%. Local Rent Control: None in Fremont. Just-Cause Eviction: Required after 12 months (AB 1482).

Renting an ADU for less than 30 days violates FMC 18.190.005 and California Gov. Code 65852.2(a)(6). Fremont actively monitors Airbnb/VRBO listings tied to Fremont addresses. Administrative citations begin around $100 and escalate with repeat violations. The recorded ADU covenant against short-term rental can be enforced through injunctive action and revocation of the Certificate of Occupancy. Violating AB 1482 eviction protections exposes the owner to tenant damages of 3x rent plus relocation assistance under Civil Code 1946.2(d).

Garage Conversions

Fremont allows garage-to-ADU conversions by right under state law without replacement parking. Building permit required. Ministerial 60-day review.

Key details: ADU Conversion: Allowed by right. Replacement Parking: Not required. Ceiling Height: 7 ft minimum. Review: 60 days ministerial. Non-ADU Conversion: Building permit required.

Contact your local code enforcement office for specific penalty information.

The rules around garage conversions in Fremont lean permissive, but that does not mean anything goes.

ADU Rules

Fremont follows CA Gov Code 65852.2: ADUs up to 1,200 sq ft allowed on most residential lots, plus Junior ADUs. Ministerial 60-day review. No owner-occupancy through 2025.

Key details: Max Detached Size: 1,200 sq ft. Setback Minimum: 4 ft side and rear. Parking: Often waived near transit. Review Time: 60 days ministerial. JADU: Up to 500 sq ft in primary home.

Contact your local code enforcement office for specific penalty information.

Fremont is more permissive than most cities when it comes to adu rules. That said, there are still limits.

Shed Rules

Fremont allows backyard sheds up to 120 sq ft without a building permit. Larger sheds need permits and setbacks. Zoning limits rear and side yard coverage.

Key details: Permit-Free Size: 120 sq ft or less. Setback: 3 ft side and rear. Height: 10 ft max. Electrical or Plumbing: Permit required. VHFHSZ: Ignition-resistant within 30 ft.

Contact your local code enforcement office for specific penalty information.

Fremont is more permissive than most cities when it comes to shed rules. That said, there are still limits.

The Bottom Line

Compared to many U.S. cities, Fremont gives residents more room on accessory structures. 5 of the 9 rules here are rated permissive. But permissive does not mean unregulated. There are still requirements, and the city does enforce them when violations are reported.

These rules come from Fremont's publicly available municipal code. For complete penalty schedules, exemption details, and answers to common questions, see the individual ordinance pages throughout this guide.