ADU Rules in Berkeley, CA (2026)

Berkeley, CA permits accessory dwelling units (ADUs) on residential properties. ADUs — also called granny flats, in-law units, backyard cottages, or secondary suites — are secondary housing units on a single-family or multifamily lot. California state law actively preempts local restrictions, making ADU approval a streamlined ministerial process. In Berkeley, the Berkeley Planning and Development Department — Building Services handles ADU permit applications. Below you will find the current size limits, setbacks, fees, and timeline for building an ADU in Berkeley.

ADU Size Limits

ADU Size Limits in Berkeley: Detached ADU: up to 1200 sq ft (max height: 16 feet). Attached ADU: 50% of primary dwelling up to 1200 sqft. Junior ADU (JADU): up to 500 sq ft — must be within the existing primary dwelling or accessory structure. Detached ADU maximum 1,200 sqft per California Gov Code 65852.2(c)(2)(B). JADU maximum 500 sqft within existing primary structure per Gov Code 65852.22. Berkeley has some of the highest rental rates in the Bay Area — even a small JADU can rent for $2,500–$4,000/month due to UC Berkeley proximity. Berkeley BMC Section 23C.24.110.

Permit Fees

ADU Permit Fees in Berkeley: Plan check fee: $700–$4,000. Building permit fee: $1,200–$5,500. Impact fees: None. School fees: Exempt for ADUs under 750 sqft. ADUs 750+ sqft subject to Berkeley Unified School District developer fees.. Total estimated permit cost: $2,500–$10,000 total permit fees. Impact fees waived for ADUs under 750 sqft per Gov Code 65852.2(f)(3). EBMUD connection fees for new water/sewer service (typically $4,000–$10,000 depending on meter size). Berkeley's ADU permit fees are among the Bay Area's more transparent — full schedule at cityofberkeley.info/permits/fees. Fee schedule: https://www.cityofberkeley.info/planning/fees/

Permit Timeline

Berkeley ADU Permit Timeline: Berkeley Planning and Development processes ADU permits. Ministerial approval within 60 days per state law. Berkeley's permit review process: 4-8 weeks for standard ADUs. Berkeley PERMIT service center at 1947 Center Street. Pre-application ADU consultations available. Construction typically 4-12 months. Apply through the Berkeley Planning and Development Department — Building Services online permit portal. Phone: (510) 981-7440.

Setback Requirements

ADU Setback Requirements in Berkeley: Front setback: Same as zone standard. Side setback: 4 feet. Rear setback: 4 feet. 4-foot side and rear setbacks per California Gov Code 65852.2(c)(2)(E). Berkeley R-1 zones typically require 5 ft side and 20 ft rear setbacks for primary dwellings — ADU setbacks at 4 ft are less restrictive by state law. Berkeley's small lots (average 5,000-6,000 sqft in flatlands) mean ADU placement requires careful site planning.

Parking Requirements

Parking Requirements: No additional parking required for ADUs within one-half mile of Downtown Berkeley BART (Downtown Berkeley station), North Berkeley BART, or Ashby BART. Berkeley's extensive AC Transit bus network also creates transit proximity zones. No replacement parking when garage converted to ADU. Per California Gov Code 65852.2(d). Berkeley proactively eliminated ADU parking requirements before state law mandated it.

Restrictions & Requirements

• •ADU must comply with Berkeley Municipal Code Section 23C.24.110 objective standards
• •Berkeley Rent Stabilization may apply to new ADUs in multifamily context — verify coverage with Berkeley Rent Board
• •ADU cannot be sold separately from primary dwelling (unless SB 9 lot split applies)
• •Short-term rental of ADR requires Berkeley Short-Term Rental registration
• •Hillside (R-1H) properties: seismic and fire safety requirements are stricter
• •Properties in UC Adjacent (UA) overlay zone may have additional design standards

How Many ADUs Are Allowed?

Number of ADUs Allowed in Berkeley: Single-family lots: 1 ADU + 1 JADU per single-family lot. Multifamily properties: Up to 25% of existing units (minimum 2) as detached ADUs; non-livable space conversions by-right per state law. Berkeley's SB 9 implementation allows urban lot splits in R-1 zones, potentially creating additional development opportunity. UC Berkeley proximity means strong demand for studio and 1-bedroom ADUs from graduate students and researchers.

State Law & Preemption

Historic District Considerations

Frequently Asked Questions