California ADU rules · Monterey County
Can I Build an ADU in Greenfield?
Yes — you can build an ADU in Greenfield. California's statewide ADU law requires every city, including Greenfield, 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
Local ruleConditional
Ministerial/by-right if all objective standards are met; discretionary review possible if not, with appeal rights.
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
Local ruleconversions (>=1 or 25% of units) + up to 8 detached (not exceeding number of existing units); up to 2 detached on lot with proposed multifamily dwelling
Detached ADUs on multifamily lots capped at 8 and cannot exceed number of existing units; up to 2 detached on proposed multifamily lots.
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 ADUs: 1,000 sq ft max if >1 bedroom; 850 sq ft if 1 bedroom or less.
Max attached ADU size
Local rule1,000 sq ft max (>1 bedroom) or 850 sq ft (1 bedroom or less); cannot exceed 50% of primary, but 800 sq ft min and 1,000 sq ft max allowed
50% rule waived to allow up to 1,000 sq ft; 850/1,000 sq ft max depending on bedroom count.
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 if near transit or for multifamily/multistory; up to 20 ft to match roof pitch if near transit.
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
Local rule6 ft
Detached ADUs must be 6 ft from primary dwelling; 5 ft from eaves of habitable structure.
Parking
Parking required
Local ruleUp to 1 space
1 off-street space per ADU (none for studios); multiple 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 when garage/carport/covered parking 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; not required 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, Deed restriction (JADU), Inspection (JADU)
JADUs require deed restriction and inspection in addition to building permit.
Greenfield-specific factors that can change the answer
State law sets the floor, but these local conditions often decide whether a specific parcel works.
Fire sprinklers
Sprinklers not required for ADUs unless required for primary dwelling; required for ADUs in multifamily buildings with sprinklers.
Historic district
No parking required for ADUs in historic districts.
Greenfield caps detached and attached ADUs at 1,000 sq ft (850 sq ft for 1-bedroom or less), requires 6 ft separation from the primary dwelling, and mandates owner-occupancy only for JADUs. Up to 8 detached ADUs are allowed on multifamily lots, but not exceeding the number of existing units.
Frequently asked questions
Can I build an ADU in Greenfield?
Yes. California's statewide ADU law requires Greenfield 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 Greenfield?
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 Greenfield?
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 Greenfield?
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 Greenfield?
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 Greenfield?
Owner-occupancy: only for a jadu. ADUs under 750 sq ft are also exempt from impact fees.
Sources
- Greenfield Municipal Code Chapter 17.90 (Ord. 574 Exh. A, 2025)
- § 17.90.050
- § 17.90.020(B), § 17.90.030(C)
- § 17.90.020(D)
- § 17.90.020(H)
- § 17.90.020(F)(5), (7)
- § 17.90.020(I)
- § 17.90.020(I)(4)(a)
- § 17.90.030(J)
- § 17.90.040
- § 17.90.020(N)
- § 17.90.020(I)(4)(b)
- Cal. Gov. Code §§ 66310–66342 (ADU Law)
- HCD 2025 Accessory Dwelling Unit Handbook
- 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 § 66317 (ministerial approval, 60-day deadline)
- 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 Greenfield'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 Greenfield Planning before relying on it.
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