California ADU rules · Merced County
Can I Build an ADU in Los Banos?
Yes — you can build an ADU in Los Banos. California's statewide ADU law requires every city, including Los Banos, 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
Local ruleconversions (up to 25% of units) + up to 2 detached
City limits detached ADUs on multifamily lots to 2 per lot, less than state default of 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 rule1,000 sq ft
Detached ADUs: 850 sq ft (studio/1-bed), 1,000 sq ft (2-bed); no more than 2 bedrooms.
Max attached ADU size
Local rule850/1,000 sq ft cap and 50% of primary; cannot be reduced below 800 sq ft
Attached ADUs capped at 850/1,000 sq ft and 50% of primary, 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
CA state law500 sq ft
Max height
Local rule16 ft
Detached ADUs: 16 ft, 1 story; above-garage ADUs must comply with base zone height.
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
Local ruleper base zone (typically 20 ft, or 10 ft on cul-de-sac bulbs)
Front setback per underlying zoning; cannot block state-mandated ADU.
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
Max 1 space per ADU; JADUs require none; multiple 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
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
Local ruleOnly for a JADU
Owner-occupancy waived for ADUs permitted 2020–2025; required after. JADUs always require owner-occupancy unless exempt.
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
CA state lawBuilding permit
Only a ministerial building permit — no conditional use permit or discretionary design review for a qualifying ADU.
Los Banos-specific factors that can change the answer
State law sets the floor, but these local conditions often decide whether a specific parcel works.
Historic District
No parking required for ADUs in historic districts.
Los Banos limits detached and attached ADUs to 850 sq ft (studio/1-bed) or 1,000 sq ft (2-bed), and allows only 2 detached ADUs on multifamily lots. Owner-occupancy for ADUs is waived through 2024, but required after.
Frequently asked questions
Can I build an ADU in Los Banos?
Yes. California's statewide ADU law requires Los Banos 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 Los Banos?
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 Los Banos?
Side and rear setbacks are limited to 4 ft. per base zone (typically 20 ft, or 10 ft on cul-de-sac bulbs).
Is parking required for an ADU in Los Banos?
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 Los Banos?
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 Los Banos?
Owner-occupancy: only for a jadu. ADUs under 750 sq ft are also exempt from impact fees.
Sources
- Los Banos Municipal Code, Article 30 (ADUs), §§ 9-3.3000 et seq.; Ord. 1170 (2019), Ord. 1190 (2021)
- § 9-3.3003(c), (d)
- § 9-3.3005(d)(1)
- § 9-3.3005(d)(2)-(3)
- § 9-3.3005(c)
- § 9-3.3005(b), § 9-3.609
- § 9-3.3007(a)-(d)
- § 9-3.3006(c), (d); § 9-3.3004(c)
- § 9-3.3007(d)(3)
- 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 § 66311.5 (impact fees: none for an ADU ≤ 750 sq ft or JADU ≤ 500 sq ft)
Last updated May 21, 2021. This is an AI-assisted summary of Los Banos'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 Los Banos Planning before relying on it.
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