California ADU rules · Riverside County
Can I Build an ADU in Corona?
Yes — you can build an ADU in Corona. California's statewide ADU law requires every city, including Corona, 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 ruleMaximum of two units in any combination: (1) one detached ADU + one JADU, (2) one detached ADU + one attached/internal ADU, or (3) two JADUs
Allows two JADUs or a detached ADU plus an attached/internal ADU, which is broader than the state baseline.
Units on a multifamily lot
Local ruleConversions: at least one ADU or JADU within existing non-livable space, up to 25% of existing units; Detached: up to 8 detached ADUs, not to exceed the number of existing units; Proposed multifamily: up to 2 detached ADUs
Detached ADUs on multifamily lots capped at the number of existing units; up to 2 detached ADUs for proposed multifamily.
Junior ADU (JADU)
Local ruleAllowed
JADUs allowed within existing or proposed single-family dwellings.
Size & height
Max detached ADU size
Local rule1,200 sq ft
Local maximum is 1,200 sq ft; cannot preclude at least 800 sq ft.
Max attached ADU size
Local rule50% of primary, >=800
Attached ADU max is 50% of primary unit, but not less than 800 sq ft.
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
Local rule500 sq ft
JADU maximum size is 500 sq ft.
Max height
CA state law16 ft
16 ft baseline; cities must allow 18 ft within ½ mi of a major transit stop or where the primary dwelling is two-story, and 20 ft on a lot with a multistory multifamily building.
Setbacks
Side setback
Local rule4 ft
4 ft minimum for new construction; conversions may have zero setback.
Rear setback
Local rule4 ft
4 ft minimum for new construction; conversions may have zero setback.
Front setback
Local ruleMust comply with underlying zone, except state law preempts for 800 sq ft ADUs
Front setback per base zone, but state preemption applies for 800 sq ft ADUs.
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 space per unit or per bedroom (whichever is less) for new ADUs; no parking for conversions.
Transit parking exemption
CA state lawYes — no parking required near transit & for conversions
No parking may be required within ½ mi walking distance of transit, in a historic district, for an ADU within an existing structure, within one block of car-share, or in certain permit-parking areas.
Garage-conversion replacement parking
Local ruleNot required
No replacement parking required when garage/carport/parking space is converted.
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
Owner occupancy required for JADUs only.
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 for JADUs
JADUs require a deed restriction in addition to a building permit.
Corona-specific factors that can change the answer
State law sets the floor, but these local conditions often decide whether a specific parcel works.
Sprinkler requirement
ADU must have sprinklers if the primary unit requires them.
Historic district parking exemption
No additional parking required for ADUs in historic districts.
Corona allows up to two ADUs in flexible combinations on single-family lots, including two JADUs, and caps detached ADUs at 1,200 sq ft. Sprinklers are required for ADUs if the primary dwelling requires them.
Frequently asked questions
Can I build an ADU in Corona?
Yes. California's statewide ADU law requires Corona 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 Corona?
A detached ADU of at least 1,200 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 Corona?
Side and rear setbacks are limited to 4 ft. Must comply with underlying zone, except state law preempts for 800 sq ft ADUs.
Is parking required for an ADU in Corona?
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 Corona?
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 Corona?
Owner-occupancy: only for a jadu. ADUs under 750 sq ft are also exempt from impact fees.
Sources
- Corona Municipal Code Chapter 17.85 (Ord. 3410, 2025)
- § 17.85.030(K)(1)
- § 17.85.030(K)(2)-(3)
- § 17.85.050(D)(2)
- § 17.85.040(D), (E)
- § 17.85.040(D)
- § 17.85.040(F)
- § 17.85.040(B), (C)
- § 17.85.040(B)(2)
- § 17.85.050(B)
- § 17.85.050(D)
- § 17.85.040(J)
- § 17.85.040(C)(2)
- 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 § 66323 (by-right ADU/JADU, 800 sq ft, 4-ft setbacks)
- Cal. Gov. Code § 66322 (ADU parking; § 66334 covers JADU parking)
- 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 Corona'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 Corona Planning before relying on it.
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