Can I Build an ADU in Roseville?

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 2 detached (proposed MF) or up to 8 detached (existing MF)

Up to 2 detached ADUs on a lot with a proposed multifamily dwelling, or up to 8 detached ADUs (not exceeding the number of existing units) on a lot with an existing multifamily dwelling, plus conversions of non-livable space (≥1, up to 25% of existing units).

Allowed

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

1,000 sq ft

Roseville caps a detached ADU at 850 sq ft (studio/1-bedroom) or 1,000 sq ft (2+ bedrooms) — below the 1,200 sq ft state default. At least 800 sq ft must still be allowed via the state-mandated 4-ft-setback path even where this cap would otherwise apply.

850 sq ft (studio/1-bed) or 1,000 sq ft (2+ bed), and not exceeding the primary dwelling's floor area; up to 150 sq ft may be added for ingress/egress

Roseville sizes attached ADUs by the same 850/1,000 sq ft caps as detached, additionally bounded by the primary dwelling's floor area (state law guarantees ≥850 / ≥1,000 sq ft regardless).

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

No front setback may block the mandatory 800 sq ft / 16-ft / 4-ft-setback ADU; otherwise per base zone

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)

Ministerial/by-right when the ADU or JADU meets every Chapter 19.60 standard; an ADU that does not meet those objective standards instead needs a discretionary Administrative Permit.

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 requirement for ADUs (the prior sunset was removed). A JADU may require owner-occupancy, principally where it shares sanitation with the main house.

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

A ministerial building permit for a compliant ADU/JADU; a non-compliant project requires a discretionary Administrative Permit in addition.