Can I Build an ADU in Villa Park?

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).

1,200 sq ft

Detached ADUs are capped at 1,200 sq ft on lots under 1 acre; 1,500 sq ft on lots 1 acre or larger.

1,200 sq ft or 50% of primary unit (whichever is less) for <1 acre; 1,500 sq ft or 50% of primary unit (whichever is less) for 1+ acre

Attached ADUs are capped at 1,200 sq ft or 50% of primary (whichever is less) on lots under 1 acre; 1,500 sq ft or 50% of primary (whichever is less) on lots 1 acre or larger.

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

30 ft

Two-story detached ADUs may be up to 30 ft; 16 ft for 1-story detached; 18 ft if within 1/2 mile of major transit.

4 ft

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

4 ft

50 ft for detached ADUs, may be reduced if unduly constraining (Planning Dept. discretion)

Detached ADUs require 50 ft front setback unless found unduly constraining.

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 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

Planning and plan check fees waived if owner-occupancy covenant is recorded or if garage/carport conversion provides 2 covered spaces for primary residence.