ADU rules in South Orange

ADUs are permitted on lots that contain detached single-family or two-family dwellings in the RA-50, RA-60, RA-75, RA-100, and RB zones, either by converting an existing accessory structure or by new construction of an accessory structure. Detached ADUs may not be located forward of the front wall of the principal building, must be set back at least 20 feet from the principal building and 10 feet from any other accessory structure, and may not exceed 25 feet in height. New detached ADUs must use exterior materials and architectural character complementary to the principal building.

The code defines an ADU as a self-contained portion of a principal one-family dwelling, two-family dwelling, or an accessory structure, used as a secondary housing unit independent of the primary dwelling unit. However, an ADU may not be situated or contained within any basement, cellar, or attic; the village FAQ adds that ADUs must be above ground with full access to light and air.

The code sets both a floor (at least 350 square feet) and a ceiling (not more than 750 square feet), requires all ADUs to have less total square footage than the principal dwelling and no more than two bedrooms, and limits ADU height to 25 feet. The ADU definition also requires the unit to be smaller in size and height than the principal building on the lot.

The ADU must be in common ownership with the principal dwelling unit and the principal dwelling must be owner occupied. The ADU definition itself requires the owner to live on site, and the village FAQ states explicitly that you cannot rent out an ADU without living on the property.

A minimum of one additional off-street parking space per ADU is required, in a location compliant with Article XXXI of Chapter 185. One additional driveway and curb cut is allowed only if the property is a corner lot meeting the district's minimum lot area and width, the driveway is set back at least 10 feet from adjacent properties, the principal structure, and existing driveways, and any removed trees or shrubs comply with Chapter 334.

The code states ADUs shall be permitted on qualifying single-family and two-family lots in the RA-50, RA-60, RA-75, RA-100, and RB zones. The village FAQ explains that applicants whose ADUs meet the ordinance requirements obtain permits through the zoning and building departments, while proposals that do not meet the ordinance require bulk and/or use variance approval from the Zoning Board of Adjustment.

The code bars use of ADUs for short term rentals, defined elsewhere in § 185-3 as rental of a dwelling or portion of one for overnight lodging of one night up to 28 consecutive days. The ADU definition limits occupancy to one family/housekeeping unit for 90 days or greater, and the village FAQ confirms ADUs cannot be used as Airbnbs, with the stated intent of creating longer-term housing. Because owner occupancy of the principal dwelling is required, the ADU cannot be rented out by an absentee owner.