Berkeley's Accessory Structures: The Rules That Matter

Every city handles accessory structures a little differently. In Berkeley, 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

Tiny homes on foundations qualify as ADUs under Berkeley and state law. Tiny homes on wheels (THOWs) are not permitted as permanent dwellings; RV-parked living is prohibited.

Key details: Tiny home on foundation: Allowed as ADU. THOW on wheels: Not permitted as dwelling. Min ceiling: 7 ft (loft exceptions). Approval: 60 days ministerial. RV living: Prohibited.

Contact your local code enforcement office for specific penalty information.

Shed Rules

Sheds under 120 sq ft and 12 ft tall are permit-exempt in Berkeley. Larger structures need permits, fire zone sheds must meet WUI standards, and setbacks apply to all sheds.

Key details: Permit exempt: Under 120 sq ft, 12 ft tall. Setbacks: 4 ft rear/side. VHFHSZ: WUI Chapter 7A applies. No sleeping: Not a dwelling. Electrical: Triggers permit.

Contact your local code enforcement office for specific penalty information.

Carport Rules

Carports require building permits and must meet setbacks. Front-yard carports are restricted; fire zone carports need WUI-compliant materials.

Key details: Permit: Required all sizes. Setbacks: 4 ft rear/side. Front yard: Restricted. VHFHSZ: WUI Chapter 7A. Fabric/tarp: Nuisance risk.

Contact your local code enforcement office for specific penalty information.

Garage Conversions

Berkeley allows garage-to-ADU and garage-to-JADU conversions under BMC 23.306, consistent with California Government Code §65852.2. No replacement parking is required when a garage is converted to an ADU, and the existing garage's setbacks are preserved for the converted footprint.

Key details: Code Section: BMC 23.306; CA Gov Code §65852.2. Replacement Parking: Not required. Existing Setbacks: Preserved for conversion footprint. Conversion Expansion: Up to 150 sq ft for ingress/egress. Permit Required: Yes — building permit.

Converting a garage to living space without a building permit is a Berkeley code violation that may trigger stop-work orders, fines, and required restoration of the garage. Self-certified 'unpermitted' conversions are not eligible for the BMC 23.306 ministerial path until properly permitted.

If you are coming from a city with tighter rules, you will find Berkeley gives residents more flexibility on garage conversions.

ADU Rental Restrictions

Berkeley prohibits short-term rentals (under 14 days) of any ADU under BMC Chapter 23.318 and the Short-Term Rental Ordinance (BMC 23.318). Long-term ADU rentals (30+ days) are subject to Berkeley's Rent Stabilization Ordinance (BMC 13.76) - however, newly constructed ADUs are exempt from rent ceiling under the Costa-Hawkins Rental Housing Act.

Key details: STR Min Stay: 14 days (BMC 23.318). ADU as STR: Not eligible (not primary residence). Rent Control: Yes (BMC 13.76) for long-term rentals. Costa-Hawkins Exemption: New ADUs (post-2/1/1995). Just-Cause Eviction: Required (BMC 13.76.130).

Operating an illegal STR violates BMC 23.318 with administrative citations up to $1,500 per day per violation (BMC 1.28). Berkeley actively monitors Airbnb/Vrbo listings and issues citations to non-compliant hosts. Failing to register an ADU rental with the Rent Board violates BMC 13.76; the Rent Board can suspend the property owner's right to collect rent and may award double rent restitution to tenants.

This is not one of those rules that cities tend to ignore. Berkeley actively enforces its adu rental restrictions requirements.

ADU Permits

Berkeley processes ADU permits ministerially under Berkeley Municipal Code Section 23.304 (Accessory Dwelling Units) and California Government Code 65852.2. Applications go through the Permit Service Center; the city must act within 60 days of a complete application. Berkeley imposes design review only when state law allows.

Key details: Code Section: BMC 23.304. Review Type: Ministerial (no hearing). Decision Window: 60 days from complete app. Submittal Portal: Berkeley Permit Service Center. Allowed Districts: R-1 through R-4 + multifamily.

Operating an ADU without a building permit is a code violation under BMC 19.04 (Building Code) and BMC 23.104 (zoning enforcement). Penalties include stop-work orders, administrative citations starting at $100 (BMC 1.28), daily continuing-violation fines, and an order to legalize or remove the unit. Unpermitted ADUs can block sale or refinancing of the property.

ADU Owner Occupancy

Under BMC 23.304 and California Government Code 65852.2(a)(8), Berkeley 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 code-compliance citations under BMC 1.28 starting at $100. Berkeley 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 Berkeley gives residents more flexibility on adu owner occupancy.

ADU Impact Fees

Under California Government Code 65852.2(f)(3) and BMC 23.304, Berkeley 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. Berkeley's permit fees themselves remain among the highest in the East Bay.

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-$8,000 (any size). Housing Trust Fund Fee: Waived under 750 sq ft.

Berkeley cannot legally charge impact fees on a sub-750 sq ft ADU. If charged in error, the homeowner may request a refund through Finance or sue under California Code of Civil Procedure 1085. The Mitigation Fee Act (Gov. Code 66020) allows protest of impact fees within 90 days of payment with statutory due-process requirements.

ADU Rules

Berkeley regulates ADUs and JADUs under Berkeley Municipal Code Chapter 23.306. One ADU plus one JADU is allowed per single-family lot citywide (Hillside Overlay allows one ADU OR one JADU). New detached ADUs are limited to 16 feet in height, with a 4-foot minimum side and rear setback, and JADUs are capped at 500 sq ft within the existing dwelling.

Key details: Code Section: BMC 23.306 (Development Standards 23.306.030). Units Allowed: 1 ADU + 1 JADU per single-family lot. Side/Rear Setback: 4 ft (new construction). JADU Max Size: 500 sq ft (within dwelling). STR Use: Prohibited by deed restriction.

Unpermitted ADUs are code violations enforced by Berkeley Land Use Planning and Building & Safety, with potential fines and stop-work orders. Using a Berkeley ADU as a short-term rental violates both the recorded deed restriction and BMC Chapter 23.314 (the STR ordinance).

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

The Bottom Line

Compared to many U.S. cities, Berkeley gives residents more room on accessory structures. 3 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.

All of the above reflects Berkeley's municipal code as of our last review. If you need specifics on fines, exemptions, or filing requirements, the detailed ordinance pages linked above have the full breakdown.