California ADU rules · San Luis Obispo County
Can I Build an ADU in Morro Bay?
Yes — you can build an ADU in Morro Bay. California's statewide ADU law requires every city, including Morro Bay, 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 detached OR 1 attached ADU + 1 JADU
Only one ADU (detached or attached) plus one JADU allowed per single-family lot.
Units on a multifamily lot
Local ruleup to 2 detached ADUs + conversions (>=1 or 25% of units)
Limits detached ADUs on multifamily lots to 2, not 4 or 8.
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 rule1,200 sq ft
1,200 sq ft for 2+ bedrooms; 1,000 sq ft for studio/1-bedroom.
Max attached ADU size
Local rule1,000 sq ft maximum
Attached ADUs capped at 1,000 sq ft regardless of primary dwelling size.
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
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
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 ruleNone
No parking required for ADUs except in the coastal overlay zone.
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 conversions except in the coastal overlay.
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 only for JADUs, not for ADUs.
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, Coastal development permit (in CRP overlay)
Coastal development permit required in the coastal resource protection overlay.
Morro Bay-specific factors that can change the answer
State law sets the floor, but these local conditions often decide whether a specific parcel works.
Coastal Resource Protection (CRP) Overlay
Coastal development permit required; stricter parking and siting rules may apply.
Morro Bay limits detached ADUs on multifamily lots to 2 and caps attached ADUs at 1,000 sq ft. Coastal overlay areas require a coastal development permit and may have stricter parking and siting rules.
Frequently asked questions
Can I build an ADU in Morro Bay?
Yes. California's statewide ADU law requires Morro Bay 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 Morro Bay?
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 Morro Bay?
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 Morro Bay?
None. 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 Morro Bay?
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 Morro Bay?
Owner-occupancy: only for a jadu. ADUs under 750 sq ft are also exempt from impact fees.
Sources
- Morro Bay Municipal Code § 17.30.040 (Ord. No. 662, § 2, 12-13-23)
- MBMC § 17.30.040(C)
- MBMC § 17.30.040(D)(1)(a)
- MBMC § 17.30.040(D)(1)(b)
- MBMC § 17.30.040(G)
- MBMC § 17.30.040(F)(2)
- MBMC § 17.30.040(E)(4)(d)
- MBMC § 17.30.040(J)(2); § 17.14.040(B)
- MBMC § 17.14.040(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 § 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 § 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 Morro Bay'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 Morro Bay Planning before relying on it.
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