California ADU rules · San Bernardino County
Can I Build an ADU in Colton?
Yes — you can build an ADU in Colton. California's statewide ADU law requires every city, including Colton, 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 (>=1 or 25% of units) + up to 2 detached (proposed multifamily) or up to 8 detached (existing multifamily), not to exceed number of existing units
Local cap on detached ADUs for multifamily: 2 for proposed, 8 for existing, and total detached cannot exceed number of existing units.
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; 850 sq ft for studio/1-bedroom. No local cap below state default.
Max attached ADU size
Local rule1,200 sq ft for 2+ bedrooms; 850 sq ft for studio/1-bedroom; further limited to 75% of primary dwelling, but never less than 800 sq ft
Local 75% of primary dwelling cap, 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 rule35 ft
Detached: 35 ft standard; 30 ft (2 stories) within 1/2 mile of major transit or on multifamily; 32 ft if needed for roof pitch. Attached: 35 ft or primary dwelling height, whichever is lower, and max 2 stories.
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 rule25 ft (for ADUs requiring an ADU permit)
25 ft front setback required for new ADUs; conversions exempt if in same location/dimensions.
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 off-street space per ADU; exemptions for transit, historic, conversions, parking permit, or car share.
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 ruleNot required
No owner-occupancy required for ADUs permitted before Jan 1, 2025; required after. JADUs always require owner-occupancy.
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, ADU permit
Both building and ADU permit required.
Colton sets a 35 ft height limit for detached and attached ADUs (with transit and multifamily exceptions), requires a 25 ft front setback for new ADUs, and limits detached ADUs on multifamily lots to 2 (proposed) or 8 (existing). Owner-occupancy is required for ADUs permitted after Jan 1, 2025, and always for JADUs.
Frequently asked questions
Can I build an ADU in Colton?
Yes. California's statewide ADU law requires Colton 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 Colton?
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 Colton?
Side and rear setbacks are limited to 4 ft. 25 ft (for ADUs requiring an ADU permit).
Is parking required for an ADU in Colton?
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 Colton?
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 Colton?
Owner-occupancy: not required. ADUs under 750 sq ft are also exempt from impact fees.
Sources
- Colton Municipal Code, Zoning Code Section 18.58 (2023)
- Colton Zoning Code §18.58(d)(1)(B)-(D)
- Colton Zoning Code §18.58(f)(1)(A)
- Colton Zoning Code §18.58(f)(1)(A)-(B)
- Colton Zoning Code §18.58(e)(2)(A)-(D)
- Colton Zoning Code §18.58(f)(2)(A)-(C)
- Colton Zoning Code §18.58(f)(6)(A)-(C)
- Colton Zoning Code §18.58(d)(3)(B), (e)(7)(A)-(C)
- Colton Zoning Code §18.58(d)(2)(A), (f)(1)(A)
- 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 2026-06-25. This is an AI-assisted summary of Colton'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 Colton Planning before relying on it.
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