California ADU rules · Los Angeles County
Can I Build an ADU in Rolling Hills Estates?
Yes — you can build an ADU in Rolling Hills Estates. California's statewide ADU law requires every city, including Rolling Hills Estates, 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 internal or attached ADU + 1 JADU per parcel
Specifies 'internal or attached' ADU, not detached, in combination with JADU.
Units on a multifamily lot
Local ruleAt least 1 internal ADU (up to 25% of units in non-livable space); up to 8 detached ADUs (not to exceed number of existing units); up to 2 detached ADUs on parcel with proposed multifamily dwelling
Adds local cap of 8 detached ADUs and clarifies rules for proposed multifamily dwellings.
Junior ADU (JADU)
CA state lawAllowed
Up to 500 sq ft, within the walls of an existing single-family home (single-family lots only).
Size & height
Max detached ADU size
Local rule1,000 sq ft
Detached ADU max: 850 sq ft (1 bedroom or less), 1,000 sq ft (more than 1 bedroom); 800 sq ft if combined with JADU.
Max attached ADU size
Local rule850 sq ft (1 bedroom or less); 1,000 sq ft (more than 1 bedroom); max 800 sq ft if >50% of primary dwelling
Local cap for attached ADUs; 800 sq ft if >50% of primary dwelling.
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
16 ft standard; 18 ft near transit or for multifamily/multi-story; attached ADUs up to 25 ft or primary dwelling height, whichever is less.
Setbacks
Side setback
CA state law4 ft
A city cannot require more than 4 ft side or rear setback; conversions of existing structures are exempt.
Rear setback
CA state law4 ft
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 space per attached/detached ADU; no parking for internal ADUs; state exemptions apply.
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 for garage/carport conversion.
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
CA state lawOnly for a JADU
No owner-occupancy requirement for ADUs (the prior sunset was removed). A JADU may require owner-occupancy, principally where it shares sanitation with the main house.
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, Administrative permit
Both building and administrative permits required.
Rolling Hills Estates-specific factors that can change the answer
State law sets the floor, but these local conditions often decide whether a specific parcel works.
Very High Fire Hazard Severity Zone (VHFHSZ)
ADUs must comply with all applicable building, health, and fire codes; sprinklers not required unless for primary dwelling.
Historic Resource
Additions to designated historic resources must be inset or separated by a connector offset at least 18 inches from the parallel side or rear wall.
Horse Overlay (H District)
Horsekeeping standards should be maintained where possible, but cannot preclude ADU development.
Rolling Hills Estates imposes local maximum ADU sizes (850/1,000 sq ft) and limits detached ADUs on multifamily lots to 8. Both building and administrative permits are required. Horse overlay and historic resource rules may affect ADU placement.
Frequently asked questions
Can I build an ADU in Rolling Hills Estates?
Yes. California's statewide ADU law requires Rolling Hills Estates 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 Rolling Hills Estates?
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 Rolling Hills Estates?
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 Rolling Hills Estates?
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 Rolling Hills Estates?
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 Rolling Hills Estates?
Owner-occupancy: only for a jadu. ADUs under 750 sq ft are also exempt from impact fees.
Sources
- Rolling Hills Estates Municipal Code, Chapter 17.56 (Ord. No. 752, § 3(Exh. A), 8-26-2025)
- §17.56.050(A)
- §17.56.050(B)
- §17.56.060(A)(4)
- §17.56.060(A)(1)-(3)
- §17.56.060(C)
- §17.56.080(A)-(B)
- §17.56.080(C)
- §17.56.030(A), §17.56.040
- §17.56.060(E)
- §17.56.060(J)
- §17.56.060(O)
- 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 § 66333 (junior ADUs)
- 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 § 66315 (owner-occupancy)
- 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 Rolling Hills Estates'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 Rolling Hills Estates Planning before relying on it.
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