Accessory Dwelling Unit (ADU) Maximum Size Standards in Long Beach
In the City of Long Beach, the maximum size for a new "Conforming ADU" is restricted to 50 percent of the gross floor area (GFA) of the primary dwelling or 800 square feet, whichever is less. Exceptions exist for conversions of existing nonconforming units, which may be up to 1,200 square feet, while sites with primary dwellings smaller than 1,280 square feet are permitted an ADU of up to 640 square feet.
Accessory Dwelling Unit Size Requirements
The City of Long Beach distinguishes between two primary categories of ADUs: Limited ADUs, which are created entirely from existing floor area, and Conforming ADUs, which involve new construction or expansion [Section 21.51.276.B].
Conforming ADU Size Limits
For projects involving new floor area, the Long Beach Municipal Code establishes maximum size thresholds based on the size of the primary residence and the number of bedrooms.
| Development Standard | Conforming ADU Requirement |
|---|---|
| Maximum Unit Size (Standard) | 50% of GFA of the primary dwelling, or 800 sq. ft., whichever is less [Table 51.276-1] |
| Maximum Size (Small Primary Dwelling) | Up to 640 sq. ft. if the primary dwelling is less than 1,280 sq. ft. [Section 21.51.276 - Note j] |
| Maximum Size (Nonconforming Conversion) | 1,200 sq. ft. for the conversion of an existing nonconforming second dwelling unit [Section 21.51.276.E.4.a.ii] |
| Minimum Size (0 Bedrooms) | 300 sq. ft. [Table 51.276-1] |
| Minimum Size (1 Bedroom) | 450 sq. ft. [Table 51.276-1] |
| Minimum Size (2 Bedrooms) | 750 sq. ft. [Table 51.276-1] |
Limited ADU Size Limits
A Limited ADU in the City of Long Beach is created solely from the existing floor area of a primary dwelling or an accessory structure [Section 21.51.276.B.1].
- Maximum Size: Limited to the existing footprint; no addition of floor area or expansion of the building footprint is permitted [Section 21.51.276.B.1].
- Minimum Size: 180 square feet for all Limited ADUs [Table 51.276-1].
Related Square Footage Regulations
Calculation of Area
In the City of Long Beach, the accessory dwelling unit's gross floor area is calculated in accordance with Section 21.15.1070. This GFA is counted toward the total lot coverage and floor area ratio (FAR) allowed for the specific zoning district, unless otherwise exempt [Section 21.51.276 - Note f].
Conversion of Nonconforming Units
If a property owner in the City of Long Beach seeks to convert an existing nonconforming second dwelling unit into a legal ADU, the unit may be exempt from standard maximum size limits provided the resulting ADU is not larger than 1,200 square feet [Section 21.51.276.E.4.a.ii].
Sections Cited
- Section 21.15.045 - Accessory dwelling unit.
- Section 21.15.1070 - Floor area, gross (GFA).
- Section 21.51.276 - Accessory Dwelling Units.
- Table 51.276-1 - Accessory Dwelling Unit Development Standards.