Carson, CA Accessory Structures: ADU Rules (2026)
ADU rules in Carson, CA, also called accessory dwelling unit regulations or granny flat ordinances, cover setbacks, owner-occupancy, parking, and permit requirements.
Key Facts
- Detached ADU height
- 1 story, 16 feet
- Above-garage ADU height
- 2 stories allowed
- Detached ADU max size
- 1,200 sq ft
- Governing section
- CMC § 9122.1(E)
Summary
Carson caps detached ADUs at one story and 16 feet, and limits size to 1,200 square feet detached or up to 1,000 square feet attached, under its local zoning ADU standards.
Building Height. Detached accessory dwelling units shall not exceed one (1) story and a height of sixteen (16) feet. Notwithstanding the foregoing, an accessory dwelling unit constructed above a detached garage shall not exceed two (2) stories (garage with one (1) story above) and the maximum allowable height of the underlying zoning district.
4. Unit Size.
a. The maximum size of a detached accessory dwelling unit is one thousand two hundred (1,200) square feet.
b. The maximum size of an attached accessory dwelling unit is eight hundred fifty (850) square feet for a studio or one (1) bedroom unit and one thousand (1,000) square feet for a unit with more than one (1) bedroom, or fifty (50) percent of the floor area of the existing primary dwelling, whichever is smaller.
c. The size limitations set forth in subsections (E)(4)(a) and (E)(4)(b) of this Section shall not apply to accessory dwelling units that are converted as part of a proposed or existing space of a principal residence or existing accessory structure.
d. Application of other development standards may further limit the size of the accessory dwelling unit beyond the limits established in subsection (E)(4)(a) of this Section, but in no case shall open space, site coverage, or floor area ratio requirements, including the requirement in subsection (E)(4)(b) of this Section, reduce the permitted size of a detached or attached accessory dwelling unit to less than eight hundred (800) square feet.
e.
Full Breakdown
Carson Municipal Code § 9122.1(E) sets the local development standards for accessory dwelling units within the underlying residential zone: a detached ADU is capped at one story and 16 feet, though an ADU built above a detached garage may reach two stories up to the zoning district's normal height limit. Size is capped at 1,200 square feet detached, and for attached units 850 square feet (studio/one-bedroom) or 1,000 square feet (more bedrooms), or 50% of the primary home's floor area, whichever is smaller, though these caps can never be pushed below 800 square feet by other standards. Note that state law (Gov. Code §§ 66310–66342) sets a floor ADU limits cannot fall below, and overrides any conflicting local restriction; Carson's own purpose clause still cites the older, superseded Gov. Code §§ 65852.2/65852.22 numbering.
Violations & Fines
An ADU exceeding these height or size caps, or one that conflicts with the setback and design-compatibility standards in § 9122.1(E), is not eligible for ministerial approval and must be redesigned or processed as a discretionary application.
Frequently Asked Questions
How tall can a detached ADU be in Carson?
Does state law override Carson's ADU size limits?
Sources & Official References
Other rules in Carson
How Carson compares: Easiest Cities to Build an ADU·California rules heatmap·Compare Carson to another location·View the California accessory structures overview
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ADU Rules in Nearby Cities
How other cities in Los Angeles County handle adu rules.