California ADU rules · Ventura County
Can I Build an ADU in Moorpark?
Yes — you can build an ADU in Moorpark. California's statewide ADU law requires every city, including Moorpark, 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
CA state law1 ADU + 1 JADU
At least one ADU and one JADU per single-family lot (a conversion ADU may also be possible).
Units on a multifamily lot
CA state lawConversion ADUs (≥1, up to 25% of units) + up to 8 detached
Conversions of non-livable space (at least 1, or up to 25% of existing units) plus up to 8 detached ADUs on a lot with existing multifamily — never exceeding the number of existing units. JADUs are single-family only.
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
CA state law1,200 sq ft
Statewide default cap for detached new-construction ADUs in the absence of a compliant local ADU ordinance. The unconditional by-right floor a city must always allow is 800 sq ft (see Guaranteed minimum size); a city with a compliant ordinance may set its own ceiling.
Max attached ADU size
CA state law50% of the primary dwelling, but ≥850 sq ft (≥1,000 sq ft for 2+ bedrooms) is always allowed
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
CA state lawUp to 1 space
At most 1 space per ADU (or per bedroom, whichever is less) — and waived in the common cases below.
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
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
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, Zoning Clearance
Moorpark § 17.28.020(G) requires approval of a (ministerial) Zoning Clearance confirming compliance with State ADU Law and the title's applicable development standards, in addition to the building permit. This is a ministerial step, not discretionary review.
Moorpark-specific factors that can change the answer
State law sets the floor, but these local conditions often decide whether a specific parcel works.
Hillside Management overlay (Ch. 17.38)
Much of Moorpark's terrain is subject to the Hillside Management chapter (17.38). On sloped lots, grading and siting review applies and the City's pre-approved ADU plans are not offered for slope sites — a custom design and additional engineering may be needed, though ADUs are not prohibited outright.
Very High Fire Hazard Severity Zones (Ventura County)
ADUs in State/Ventura-County-designated very high fire hazard severity zones must meet wildland-urban-interface fire-hardening standards, and Ventura County Fire Department access/water-supply review is required at permit stage.
Floodplain siting limit
Moorpark does not permit its pre-approved ADU plans inside a floodplain; an ADU in a FEMA flood zone requires floodplain-compliant design and additional review.
Moorpark regulates ADUs through Mun. Code § 17.28.020(G), which requires a ministerial Zoning Clearance plus a building permit and otherwise follows State ADU Law — detached up to 800–1,200 sq ft, 16 ft height (25 ft attached), 4 ft side/rear setbacks, and a 31-day minimum rental term. Moorpark offers pre-approved ADU plans (700, 900, and 1,188 sq ft), but those plans are not available for floodplain or sloped (hillside) sites, which need custom design. Feasibility is most affected by Moorpark's hillside terrain, very-high fire-hazard zones, and Ventura County Fire/water-district review. Confirm hillside, fire-zone, and floodplain status with Moorpark Community Development before relying on the pre-approved plans.
Frequently asked questions
Can I build an ADU in Moorpark?
Yes. California's statewide ADU law requires Moorpark 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 Moorpark?
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 Moorpark?
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 Moorpark?
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 Moorpark?
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 Moorpark?
Owner-occupancy: only for a jadu. ADUs under 750 sq ft are also exempt from impact fees.
Sources
- Moorpark Mun. Code § 17.28.020(G) (Accessory Dwelling Unit Standards and Requirements)
- Moorpark Mun. Code § 17.28.020(G)
- Moorpark Mun. Code Ch. 17.38 (Hillside Management)
- Moorpark Mun. Code § 17.28.020(G); Ventura County Fire review
- City of Moorpark ADU program (official ADU page)
- 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 § 66323 (by-right ADU/JADU, 800 sq ft, 4-ft setbacks)
- Cal. Gov. Code § 66333 (junior ADUs)
- Cal. Gov. Code § 66321 (size minimums & height)
- Cal. Gov. Code § 66322 (ADU parking; § 66334 covers JADU parking)
- Cal. Gov. Code § 66314 (local ordinance standards)
- 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 2026-06-28. This is an AI-assisted summary of Moorpark'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 Moorpark Planning before relying on it.
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