ADU rules in Oakland

Detached ADUs are 'Category Two' units (new attached or detached construction). A one-family lot may have one, alongside one Category One conversion and one JADU. Lots with an existing two- to four-family or multifamily building may have up to 8 detached ADUs (never more ADUs than existing units), and lots with a proposed one may have 2. In the S-9 Fire Safety Protection Combining Zone (the Oakland hills fire area), Category Two ADUs are barred unless you add an extra off-street parking space or get a disability accommodation. HCD's December 10, 2025 findings letter says state-exempt units under Gov. Code 66323 cannot be barred there. The city kept the rule anyway, reaffirming its fire-safety findings in Ord. 13894 (July 21, 2026).

One-family lots may add an attached Category Two ADU or a Category One conversion of existing space (plus up to 150 sq ft for an entrance), and a JADU of up to 500 sq ft inside the home. A building with two or more units may instead add one Category Three ADU, which is attached to or converted from the main building. If you choose a Category Three ADU, no other ADU is allowed on the lot. In the S-9 fire zone, a lot is limited to one interior Category One conversion or one JADU unless the 17.88.050(B) exceptions apply.

Multifamily Category Three ADUs are capped at 850 sq ft for a studio or 1-bedroom and 1,000 sq ft for 2 or more bedrooms. Multifamily Category One conversions are limited to the existing building envelope. The minimum size for every type is a California Building Code efficiency unit. Ord. 13894 (July 21, 2026) left all size figures unchanged.

The one-family table marks owner occupancy 'N/A' for Category One and Category Two ADUs. The two- to four-family and multifamily table says 'Not required'. The code still says the owner must live in either the JADU or the main home for every JADU (waived when the owner is a government agency, land trust, or nonprofit housing organization), and Ord. 13894 left that row unchanged. Since January 1, 2026, however, state law (Gov. Code 66333 as amended by SB 543 and AB 1154) allows a JADU owner-occupancy requirement only when the JADU shares sanitation facilities with the main home. So a JADU with its own bathroom carries no owner-occupancy duty, despite the code text.

The S-9 fire-zone exception that allows an ADU other than an interior conversion requires one extra off-street space on top of the home's required spaces, plus replacement of any spaces lost (17.88.050(B)(1)). A disability-based reasonable accommodation instead needs no extra ADU space, but lost spaces must still be replaced. Ord. 13894 left the parking rows unchanged.

An ADU application 'shall be granted ministerial approval' when it meets 17.103.080 and Chapter 17.88. The only exception is an ADU that is part of a project needing discretionary review, where the ADU review time can be extended to match. The city describes two steps: zoning approval through a Zoning Worksheet in the Online Permit Center, then a building permit. Ord. 13894 (July 21, 2026) deleted the Historic Preservation staff consultation for ADUs on California Register properties and the rule that exterior stairs must not be visible from the street.

Ord. 13894 (adopted July 21, 2026, effective that day) reworded the rental rule to 'a term of longer than thirty (30) consecutive days'. It also fixed the separate-sale cross-reference, replacing the misprinted 'Section 65852,26' with Gov. Code 66341. Municode will print the old wording until the ordinance is codified. The city's ADU page says '30 days or longer', but the code's 'longer than 30 days' controls. Oakland has no short-term rental permit program: stays under 30 days count as Bed and Breakfast or Transient Habitation activities under the Planning Code, and they are not allowed in an ADU.