Parsippany-Troy Hills, NJ Accessory Structures: ADU Rules (2026)

Section 430-50E was added 10-1-2019 by Ord. No. 2019:61 and applies in the R-1 District only. The lot must be at least 40,000 square feet with a width of at least 200 feet. The apartment needs its own separate entrance from ground level, not visible from the street, and cannot be accessible from the principal building. It cannot sit within the building footprint of the principal single-family residence, although an addition or the conversion of an attached garage is permissible if adequate off-street parking is provided for both uses. Each lot can hold no more than one principal single-family residence and one accessory apartment, and at least one off-street car parking space is required.

Size and occupancy are fixed. The floor area of a newly constructed or converted apartment cannot be less than 450 square feet or exceed 750 square feet, and no more than two persons can occupy it. A newly constructed detached apartment must be set back a minimum of 15 feet from both the rear and side lot lines. A conversion of an existing detached accessory building must meet the setback and yard requirements of an accessory building in the zone, and a newly constructed attached apartment must meet all the appropriate requirements in the zone. The design, materials and landscaping must respect the existing character of the principal residence and the neighborhood.

Affordability is the condition that defines the use. The apartment must be approved under the Township's accessory apartment program to be rented to a low- or moderate-income household. Before a building permit issues, a new deed must be recorded in the Morris County Clerk's Office restricting the apartment as affordable for at least 30 years. If the Township sewer system does not serve the unit, Morris County approval is required before Planning Board approval. The dwelling must comply with the Uniform Construction Code and Uniform Fire Code to the extent required by the Construction Official, and the lot cannot be subdivided unless each resulting lot complies with § 430-50E and the R-1 requirements.

The program has a ceiling. No more than five moderate-income affordable accessory apartments are permitted in the Township, and the permission ends on issuance of a building permit for the 10th affordable accessory apartment, if at least half of those units are rented to a low-income household.