Can I Build an ADU in San Bernardino?

Yes — by right

ADUs and JADUs are allowed by right in all residential and mixed-use zones; ministerial approval, no hearing.

1 ADU + 1 JADU

At least one ADU and one JADU per single-family lot (a conversion ADU may also be possible).

Conversion 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.

Allowed

Up to 500 sq ft, within the walls of an existing single-family home (single-family lots only).

1,000 sq ft

For an ADU created under the 'additional criteria' path (subsection (6)), San Bernardino caps the unit at 850 sq ft for a studio/one-bedroom and 1,000 sq ft for two or more bedrooms — below the 1,200 sq ft state default. The 800 sq ft by-right floor is always protected, and a smaller 'statutory' detached ADU (≤800 sq ft) under subsection (4)(a) is unaffected by this cap.

≤850 sq ft (studio/1-BR) or ≤1,000 sq ft (2+ BR), and no more than 50% of the existing primary dwelling — but never required below 800 sq ft

Attached ADUs are further limited to 50% of the existing primary dwelling's floor area; no percent/coverage/open-space limit may force the ADU below 800 sq ft.

800 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).

500 sq ft

16 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.

4 ft

A city cannot require more than 4 ft side or rear setback; conversions of existing structures are exempt.

4 ft

25-ft front-yard setback for an ADU built under subsection (6); no setback where the ADU is built in the same location and dimensions as an existing structure, and front setback may not block an 800 sq ft ADU

San Bernardino specifies a 25-ft front-yard setback for subsection (6) ADUs (side/rear stay at the 4-ft state maximum). Conversions in an existing footprint require no setback.

None required

No statewide separation requirement between the ADU and the primary dwelling.

Up to 1 space

At most 1 space per ADU (or per bedroom, whichever is less) — and waived in the common cases below.

Yes — 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.

Not required

When a garage/carport is demolished or converted to build an ADU, replacement parking cannot be required.

Ministerial (by right)

No public hearing or discretionary design review for a qualifying ADU.

60 days

The agency must act within 60 days of a complete application — and the ADU is deemed approved if it does not.

Only for a JADU

No owner-occupancy for ADUs. As required by state law, a JADU is subject to owner-occupancy — a natural person with title must reside in the primary dwelling or the JADU — unless the property is wholly owned by a government agency, land trust, or housing organization. A deed restriction is recorded before permit issuance.

Waived 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.

Building permit

Only a ministerial building permit — no conditional use permit or discretionary design review for a qualifying ADU.