Residential Additions and Accessory Dwelling Units

If you’re creating an addition on your property, there are zoning regulations that you need to be aware of. Whether you’re planning a residential addition or accessory dwelling unit, discover and research zoning information, potential permit requirements, and development standards.

Residential Additions

To get started with a residential addition:

1. Check your zoning in the Parcel Conditions and Permit History page. Search in “Parcel Conditions.” The zoning will be listed near the top of the table. 
2. Check for special site conditions such as landmarks, creeks and seismic hazards, by reviewing the Parcel Conditions.
3. Review development standards in the specific zoning district to determine allowable height, setbacks, and other requirements for your property. 
4. Special restrictions – Check if the following apply to your project:
   • New Floor Area: Although there are no floor area limits in residential zoning districts, any addition over 600 square feet (or 15% of lot area, whichever is less) requires an Administrative Use Permit (AUP). Additions after October 31, 1991 count toward the AUP threshold. Attic and basement conversions with no building expansion are not counted. 
   • New Bedrooms: In most residential districts, increasing the number of bedrooms on the property to five or more requires an AUP (for a fifth bedroom) or a Use Permit (for a sixth bedroom or greater). This regulation may apply to some rooms not labeled or used as a bedroom. Please see BMC Section 23.202.030(B) 
   • Demolition: A project that removes 50% or more of a building’s exterior walls and roof is a “demolition” under the Zoning Ordinance and requires a Use Permit, with possible review by the Landmarks Preservation Commission.
5. Non-conforming conditions – Many buildings in Berkeley were built decades ago and may not “conform” to current zoning standards. Lawfully established non-conforming conditions may be maintained and repaired, but expansions or modifications of such conditions may trigger additional review, as in the following cases: 
   • Setbacks: Alterations and additions within a non-conforming setback require an Administrative Use Permit. Non-conforming setbacks may be extended vertically or horizontally, but not further reduced. 
   • Lot Coverage: Any vertical addition on a property that exceeds the maximum lot coverage requires a Use Permit. No additional coverage is allowed. 
   • Density: Any addition on a property with more dwelling units than the zoning district allows requires a Use Permit.

Accessory Dwelling Units (ADU)

Accessory Dwelling Units (ADUs) and Junior Accessory Dwelling Units (JADUs) are independent and semi-independent dwelling units with complete or partial provisions for sleeping, cooking, and sanitation. ADUs and JADUs are allowed on properties with existing or proposed single-family dwellings. ADUs are also permitted on lots that are developed with an existing duplex or multi-family units.

The City of Berkeley’s ADU Ordinance was amended in accordance with the State of California law (Government Code Sections 65852.2 and 65852.22) and became effective March 17, 2022. The City's ADU Ordinance (BMC Chapters 23.306 and 12.99) allows ADUs on properties located in a zoning district that permits residential use and provides development standards based on the location of the property. The development standards are summarized in the ADU Development Standards Information Sheet and include different development standards for properties that are located in the following zoning districts within the Hillside Overlay: R-1(H), R-2(H), R-2A(H) and ES-R.

The ADU Frequently Asked Questions Sheet provide additional guidance about the ADU Ordinance, such as the permitting process and fees, architectural design considerations, JADU design considerations, conversions of existing structures, parking, and rental and ownership.

Other Requirements

Building Permit 

All ADUs and JADUs require a building permit. Compliance with the ADU zoning and development standards is reviewed as part of the building permit process. Submit applications either in person to the Permit Service Center or through Permits Online. 

Neighborhood Notification and Fees 

When the City receives a new building permit application for an ADU, city staff mail out a notice of the application to owners and tenants of the subject, adjacent, confronting, and abutting properties within 10 working days of submission to the Planning Department. A fee of $460 is collected with the new ADU building permit application to cover the notice.  

If you received a notice of an ADU application in the mail, you can check the permit status on Permits Online. If you have questions about the design and construction of an ADU, please reach out to the applicant listed on the postcard. 

Recorded Deed Restriction 

During the permit process, you will record a deed restriction with the Clerk Recorder’s Office of Alameda County, which is required prior to the issuance of the building permit. A recorded deed restriction prohibits the use of the ADU or JADU as a short-term rental, and limits the separate sale of accessory dwellings from the primary unit. Please contact the Clerk Recorder’s Office of Alameda County for more information on how to record a deed restriction, including recording instructions and fees. 

Address Assignment 

All ADUs, except JADUs, require a new address assignment. JADUs are not eligible for a separate address because they do not meet the definition of a separate dwelling unit under the Building Code. Submit the address assignment request for your ADU to the Building and Safety Division with a non-refundable payment of $200 prior to issuance of the building permit. The City issues the address assignment prior to the final inspection. 

Permit Fees 

Calculate the estimated building permit fees for your project using the Permit Fee Estimator. The Land Use Planning Division does not assess impact fees.

ADU Funding 

The City of Berkeley is partnering with the California Housing Finance Agency (CalHFA)’s ADU Grant Program to connect qualifying owners with up to $40,000 to fund ADU predevelopment and closing costs. All funds from this program were fully reserved as of December 9, 2022.  This section will be updated if additional funding becomes available.

Other Requirements 

Newly constructed ADUs are subject to the City of Berkeley Natural Gas Prohibition Ordinance (Chapter 12.80) and the Electrification Reach Code (Local amendment to Berkeley Energy Code/Chapter 19.36)  

For more information on ADUs and JADUs, email the Land Use Planning division.