California ADU rules · Los Angeles County
Can I Build an ADU in Commerce?
Yes — you can build an ADU in Commerce. California's statewide ADU law requires every city, including Commerce, to approve a qualifying accessory dwelling unit by right, plus a junior ADU (JADU) on a single-family lot. What varies city to city are the local specifics below.
Can you build one?
ADUs allowed
CA state lawYes — by right
ADUs and JADUs are allowed by right in all residential and mixed-use zones; ministerial approval, no hearing.
Units on a single-family lot
Local rule1 ADU (attached, detached, or conversion) + 1 JADU (if ADU is detached, ≤800 sq ft, ≤16 ft height, 4-ft side/rear setbacks)
Both 1 ADU and 1 JADU allowed only if the ADU is detached, ≤800 sq ft, ≤16 ft height, and has 4-ft side/rear setbacks.
Units on a multifamily lot
Local ruleUp to 2 detached ADUs (each ≤16 ft height, 4-ft side/rear setbacks) + conversions (≥1 or up to 25% of units) from non-livable space; JADUs not permitted
Detached ADUs capped at 2 per lot; JADUs not allowed in multifamily.
Junior ADU (JADU)
Local ruleAllowed
JADUs allowed only on single-family lots, within the primary dwelling.
Size & height
Max detached ADU size
Local rule1,000 sq ft
Detached ADU max: 850 sq ft (1-bedroom), 1,000 sq ft (2-bedroom); 800 sq ft if both ADU and JADU on lot.
Max attached ADU size
Local rulelesser of 50% of primary dwelling or 850 sq ft
Attached ADU cannot exceed 50% of primary or 850 sq ft, whichever is less.
Guaranteed minimum size
CA state law800 sq ft
An 800 sq ft ADU must be allowed regardless of FAR/lot-coverage caps; a city also cannot cap an attached ADU below 850 sq ft (1,000 for 2+ bedrooms).
Max JADU size
CA state law500 sq ft
Max height
Local rule16 ft
Detached ADUs limited to 16 ft; no local transit/2-story exception.
Setbacks
Side setback
Local rule4 ft
4-ft minimum side setback for new construction, including eaves/overhangs.
Rear setback
Local rule4 ft
4-ft minimum rear setback for new construction, including eaves/overhangs.
Front setback
CA state lawNo front setback may block the mandatory 800 sq ft / 16-ft / 4-ft-setback ADU; otherwise per base zone
Separation from main house
CA state lawNone required
No statewide separation requirement between the ADU and the primary dwelling.
Parking
Parking required
Local ruleUp to 1 space
1 parking space per ADU unless exempt.
Transit parking exemption
Local ruleYes — no parking required near transit & for conversions
No parking required if within ½ mile of public transit or other state exemptions.
Garage-conversion replacement parking
CA state lawNot required
When a garage/carport is demolished or converted to build an ADU, replacement parking cannot be required.
Approval, timeline & cost
Approval path
CA state lawMinisterial (by right)
No public hearing or discretionary design review for a qualifying ADU.
Approval timeline
CA state law60 days
The agency must act within 60 days of a complete application — and the ADU is deemed approved if it does not.
Owner-occupancy
Local ruleOnly for a JADU
No owner-occupancy for ADUs approved 2020–2025; JADUs require owner-occupancy.
Impact-fee waiver
CA state lawWaived under 750 sq ft
An ADU of 750 sq ft or less pays no impact fees (the 750 sq ft threshold itself is exempt under § 66311.5); larger ADUs pay fees proportional to the primary dwelling. JADUs (≤ 500 sq ft) are exempt.
Permits required
Local ruleBuilding permit, Deed restriction
Deed restriction required for ADUs/JADUs.
Commerce-specific factors that can change the answer
State law sets the floor, but these local conditions often decide whether a specific parcel works.
Historic District
Parking exemption applies if property is in a historic district.
Commerce limits detached ADUs to 1,000 sq ft (2-bedroom) or 850 sq ft (1-bedroom), and allows only 2 detached ADUs on multifamily lots. Both an ADU and JADU are allowed on single-family lots only if the ADU is detached and ≤800 sq ft.
Frequently asked questions
Can I build an ADU in Commerce?
Yes. California's statewide ADU law requires Commerce to approve a qualifying accessory dwelling unit ministerial (by right), plus a junior ADU (JADU) on a single-family lot.
How big can an ADU be in Commerce?
A detached ADU of at least 1,000 sq ft must be allowed, and an ADU of 800 sq ft can never be zoned out by floor-area or lot-coverage limits. A JADU can be up to 500 sq ft.
What are the setback requirements for an ADU in Commerce?
Side and rear setbacks are limited to 4 ft. No front setback may block the mandatory 800 sq ft / 16-ft / 4-ft-setback ADU; otherwise per base zone.
Is parking required for an ADU in Commerce?
Up to 1 space. No parking can be required within ½ mile of transit, for conversions, or for units inside the primary home. When a garage is converted, replacement parking is not required.
How long does ADU approval take in Commerce?
A complete application must be acted on within 60 days, with ministerial (by right) — no public hearing or discretionary design review for a qualifying ADU.
Do I have to live on the property to build an ADU in Commerce?
Owner-occupancy: only for a jadu. ADUs under 750 sq ft are also exempt from impact fees.
Sources
- Commerce Municipal Code § 19.07.090 (Ord. No. 761, § 1, 8-4-2020)
- CMC § 19.07.090(D)(1)-(2)
- CMC § 19.07.090(D)(3)-(4)
- CMC § 19.07.090(D)(2)
- CMC § 19.07.090(E)(1)
- CMC § 19.07.090(E)(2)
- CMC § 19.07.090(F)
- CMC § 19.07.090(G)
- CMC § 19.07.090(J)
- CMC § 19.07.090(J)(2)
- CMC § 19.07.090(L)
- CMC § 19.07.090(K)
- CMC § 19.07.090(J)(2)(b)
- Cal. Gov. Code §§ 66310–66342 (ADU Law)
- HCD 2025 Accessory Dwelling Unit Handbook
- Cal. Gov. Code § 66317 (ministerial approval, 60-day deadline)
- Cal. Gov. Code § 66321 (size minimums & height)
- Cal. Gov. Code § 66333 (junior ADUs)
- Cal. Gov. Code § 66323 (by-right ADU/JADU, 800 sq ft, 4-ft setbacks)
- Cal. Gov. Code § 66314 (local ordinance standards)
- Cal. Gov. Code § 66311.5 (impact fees: none for an ADU ≤ 750 sq ft or JADU ≤ 500 sq ft)
Last updated 2026-06-25. This is an AI-assisted summary of Commerce's ADU rules, drawn from its published ordinance and California ADU law — general information, not legal advice, and it may be incomplete or out of date. Verify the controlling rule for your specific parcel with Commerce Planning before relying on it.
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