Code library

Westmont R districts
accessory buildings and ADUs.

Westmont limits the number, size, placement, and height of detached accessory buildings and permits ADUs on detached single-family lots.

Plain English

An R-zoned lot may have one detached garage plus up to two additional non-garage accessory buildings. Their combined footprint may not exceed 1,250 square feet, and they count toward lot coverage.

Accessory buildings are allowed in rear and street-side yards, not front yards, and must be at least 5 feet from rear and side lot lines. The height limit is 18 feet or the principal building height, whichever is less. An ADU is allowed on a detached single-family lot and does not require additional parking.

Numbers Pre-Flight checks

FieldValueSource
Accessory footprint, all buildings combined1,250 sq ft maximumSec. 7.02
Accessory height18 ft or principal height, whichever is lessSec. 7.02
Accessory rear / side setback5 ft minimumSec. 7.02
ADU parkingNo additional parking requiredSec. 7.05

Official source

Village of Westmont Zoning Ordinance · Secs. 7.02 and 7.05

Effective / last checked: Amended through May 28, 2026

These pages explain what Pre-Flight checks. Always confirm the adopted text on the city's official site.

Pre-Flight is not a permit, not legal advice, and not a substitute for a licensed design professional or the authority having jurisdiction. The city still decides.