You measure the garage, decide it would make a decent one-bedroom, and start reading. Long Beach's zoning code answers with a question of its own: are you building a Limited unit or a Conforming one? Two categories, two very different sets of standards — and one of the biggest practical differences is whether you may add a single square foot of new floor area.
The code puts the dividing line plainly:
A Limited ADU is created solely from the existing floor area of the primary dwelling or an accessory structure (§ 21.51.276(B)(1)).
No addition of floor area or expansion of the building footprint is allowed when creating one, and in exchange it is exempt from many development standards. A Conforming unit is one that adds new floor area, or that sits in a permitted residential district other than a single-family district — and it must meet the zone's standards for setbacks, height, coverage and open space (§ 21.51.276(B), (D)).
An accessory dwelling unit is a second, self-contained home on a lot that already has one. In Long Beach it is an allowed accessory use on a lot with only one detached single-family dwelling and no other principal use (§ 21.51.276).
What the city's own table says
| Standard | Limited ADU | Conforming ADU |
|---|---|---|
| Front / rear setback | Not applicable | Zone's requirement; 5 ft for detached rear |
| Side setback | Not applicable | Zone's requirement, or 5 ft, whichever is less |
| Height | Not applicable | Zone's limit, or 25 ft and 2 stories, whichever is less |
| Minimum unit size | 180 sq ft | 300 sq ft studio, 450 sq ft one-bedroom, 750 sq ft two-bedroom |
| Open space | Not applicable | 30% of the unit's gross floor area |
Source: § 21.51.276(D), Table 51.276-1. Note (d) to that table: sites in the Rancho Estates Planned Development District are limited to 13 feet and one story.
Decisions are ministerial, with a clock
Long Beach considers ADU permits ministerially — without discretionary review or a hearing — except for the categories its code lists separately, and the Director of Development Services must approve or deny within 120 days of receiving the application (§ 21.51.276). Coastal Zone applications follow the city's coastal permit process instead.
Where state law now sets the floor
This is the part to raise with a planner before you design. State ADU law forbids a city from adopting certain standards at all. Read the direction carefully: these are limits on the city, not requirements on you.
- Unit size. A local agency shall not establish a maximum ADU size below 850 square feet of interior livable space, or below 1,000 square feet for a unit with more than one bedroom (Gov. Code § 66321(b)(2)). Long Beach's published table lists a maximum of 50% of the home's gross floor area or 800 square feet, whichever is less.
- Lot size. A local ordinance's objective standards shall not include requirements on minimum lot size (Gov. Code § 66314(b)(1)). The city's table lists a 4,800-square-foot minimum lot size and a 27-foot minimum lot width.
- Coverage and open space. A city may not impose lot coverage, floor area ratio, open space or front setback rules that prevent an ADU of at least 800 square feet with 4-foot side and rear setbacks from being built (Gov. Code § 66321(b)(3)).
- Owner occupancy. For a lot with a proposed or existing single-family dwelling, no additional standards beyond the state's list may be imposed, including an owner-occupant requirement (Gov. Code § 66315). The city's code contains an owner-occupancy provision (§ 21.51.276(E)(1)(a)).
- Height. A city may not adopt a height limit below 16 feet for a detached ADU, or below 18 feet where the lot is within a half-mile walking distance of a major transit stop or high-quality transit corridor, plus 2 feet for a matching roof pitch (Gov. Code § 66321(b)(4)).
The published municipal text has not caught up with every one of these. Ask Development Services in writing which standard they are applying to your project before you pay for drawings.
Parking
Long Beach's table requires one space for the ADU, in addition to the parking required for the main house — but exempts the unit where it is within a half-mile of public transit, in a designated historic district, part of the existing home or an existing accessory structure, or where a car-share vehicle is within one block (§ 21.51.276(D), Table 51.276-2). State law lists the same exemptions and adds one: no parking may be required where on-street permits are required but not offered to the ADU's occupant (Gov. Code § 66322).
Design rules that shape the drawings
Long Beach is unusually specific about appearance and privacy (§ 21.51.276(D)(3)):
- Exterior changes and new attached units must be architecturally compatible with the main house — complementary colors, finishes and roof pitch.
- A converted garage must have its garage door removed and the opening finished to match the building.
- Windows, doors and decks on a second-story unit must use privacy measures: entrances facing away from the property line, obscured glazing, windows above eye level, or screening.
- Where a driveway abuts the unit, an 18-to-36-inch landscape strip runs the full width of the driveway.
Converting an existing nonconforming second unit
If your property has a nonconforming second dwelling unit and no more than two units total, it may be converted to a Conforming ADU. That converted unit can be exempt from the maximum size limits, provided it is smaller than the other dwelling — which then becomes the primary — and is not larger than 1,200 square feet (§ 21.51.276(E)(4)).
The unpermitted-unit path is separate
Long Beach also runs a dwelling unit amnesty program for existing units that lack a certificate of occupancy but sit in otherwise legally permitted structures. Outside the coastal zone those units are not subject to the underlying zoning's density limits, off-street parking requirements, yard and setback requirements, or other development standards that would prevent preserving the unit (§ 21.66.010, § 21.66.020). The program's own text says it is not intended for units eligible for legalization as ADUs — so the two routes are alternatives, not a menu.
Also relevant: a permit for an ADU cannot be denied over nonconforming zoning conditions, building code violations or unpermitted structures that do not threaten health and safety and are not affected by the work (Gov. Code § 66322).
Before you commit
Pull your zone's setback and height numbers, decide whether you are adding floor area, and get the city's written position on unit size, lot size and owner occupancy. Our Long Beach ADU guide and Long Beach code overview are the next stop.
Sources
- Long Beach Municipal Code § 21.51.276 — Accessory dwelling units
- Long Beach Municipal Code § 21.66 — Unpermitted dwelling unit amnesty program
- Government Code § 66314 — Local ADU ordinance requirements
- Government Code § 66315 — No additional standards on single-family lots
- Government Code § 66321 — Size and height floors
- Government Code § 66322 — Parking and nonconforming conditions
- Government Code § 66323 — Ministerial approval path
