ADU rules in New Rochelle

New Rochelle's Zoning Code has no accessory dwelling unit use of any kind, so a detached backyard cottage is not allowed anywhere in the city as of right. Full-text searches of the whole Code of the City of New Rochelle on eCode360 return zero results for 'accessory dwelling unit' and zero for 'accessory apartment'. In every one-family district (R1-20, R1-15, R1-10A, R1-10, R1-HIST, R1-WF-10, R1-CH and R1-7.5) the only permitted principal residential use is a one-family dwelling, and the permitted accessory use lists in §§ 331-30 through 331-44 authorize swimming pools, sheds, home occupations, pets, dish antennas and parking, never a second dwelling. Section 331-29A closes the door explicitly: any use not specifically listed as permitted is deemed prohibited, and only in multifamily and nonresidence districts may a lot hold more than one principal use. The one detached caretaker dwelling the code contemplates is a special-permit use for cemeteries in the ROS Recreation Open Space District (§ 331-49C(1)), not a residential ADU.

There is no attached, internal or basement ADU category either. A one-family dwelling is defined in § 331-4 as 'a detached dwelling containing only one principal non-transient dwelling unit', and a dwelling unit means space with 'independent and complete cooking, sanitary and sleeping facilities', so carving a self-contained apartment out of a one-family house creates a second dwelling unit the district does not allow. The only rental-flavored accessory use permitted in a one-family house is renting out at most one non-housekeeping room to no more than two persons, and only in an owner-occupied dwelling (§ 331-30B(2) and its parallels in every residence district); a non-housekeeping room has no kitchen and is not a dwelling unit. A genuine second unit inside a house is lawful only where two-family dwellings are a permitted principal use: the R2-7.0 Two-Family Residence District (§ 331-36A(2)) and the RMF-0.4 through RMF-2.0 and RMF-SC-4.0 multifamily districts. That is a two-family dwelling with two principal units, not an accessory unit, and it is unavailable on the great majority of New Rochelle's residentially zoned lots.

Because the code authorizes no accessory dwelling unit, it sets no floor area, footprint or height cap for one. Two nearby numbers are worth knowing and are frequently misread as ADU allowances. First, § 331-4 defines an 'accessory dwelling of caretaker, superintendent or watchman' as a unit that 'is part of the principal building', is required by the principal use for security, safety, maintenance or operation, and 'does not exceed 1,600 square feet in area'; that use is authorized only for cemeteries in the ROS district under § 331-49C(1) and is not available to a homeowner. Second, § 331-4 caps detached accessory buildings at an aggregate building area of 25% of the principal building's building area, and § 331-45A(1) keeps them 10 feet off the rear lot line, six feet off any side lot line, out of the required front yard and 10 feet away from the main building. Those accessory buildings may not contain a dwelling unit.

No owner-occupancy standard for accessory units can exist because New Rochelle authorizes no accessory units; the code is simply silent. Owner occupancy does appear in two adjacent places, which is why the answer is 'not addressed' rather than 'no'. Renting a single non-housekeeping room to at most two people is a permitted accessory use 'for owner-occupied dwellings only' in every residence district (§ 331-30B(2) and parallels), and a bed-and-breakfast is defined in § 331-4 as renting not more than three rooms 'in an owner-occupied dwelling' to not more than six transient roomers. Renting out an entire lawful one-family or two-family dwelling carries no owner-occupancy condition. New York has no statewide ADU statute that would preempt a local owner-occupancy rule in either direction.

The Schedule of Off-Street Parking and Loading Space Requirements in § 331-126 lists '1-family dwelling: 2 per dwelling unit' and '2-family dwelling: 2 per dwelling unit' with no ADU or accessory-unit row. Section 331-126 also provides that for uses that do not fall within the listed categories the Building Official recommends and the Planning Board establishes the requirement, so any hypothetical accessory unit would be assigned parking case by case. Rooming houses need 1 space per 2 guest rooms and a bed-and-breakfast needs 1 space per rented room on top of the residential requirement. Renting a single non-housekeeping room in an owner-occupied house adds no parking obligation; note separately that § 331-30B(6) caps transient parking on a one-family lot at four licensed private passenger cars.

There is no ADU permit pathway of any kind: no district lists an accessory dwelling as a permitted, accessory or special-permit use, and § 331-29A states that any use not specifically listed as permitted is deemed prohibited. The only route to a second unit on a one-family lot is a use variance from the Board of Appeals on Zoning under § 331-133F, which requires the applicant to prove unnecessary hardship for each and every permitted use in the district: no reasonable return shown by competent financial evidence, a hardship unique to the property, no alteration of the essential character of the neighborhood, and a hardship that is not self-created. That is a demanding discretionary standard, not an administrative approval. Where two-family dwellings are already permitted (R2-7.0 and the RMF districts), converting to a two-family is a by-right building permit matter subject to the district's dimensional standards and § 331-137 certificate of occupancy rules, not an ADU process.

Section 331-30B(2), repeated in each residence district, permits 'for owner-occupied dwellings only, the renting out of not more than one non-housekeeping room to not more than two persons'. Renting an entire lawful one-family or two-family dwelling is unrestricted by zoning. Bed-and-breakfast use is a special permit use only in the waterfront PWD-3, PWD-5, PWD-8 and PWDE-5 districts, so it is not available in the R1 or R2 districts. A whole-code search found no short-term rental, transient rental or hosting-platform chapter: the exact phrase 'short-term rental' appears once in the entire code, in the § 331-4 definition of a motor vehicle rental agency. Registration duties fall only on multiple dwellings, defined in § 209-1 as buildings occupied by three or more families living independently, so one- and two-family rentals are not registered. Long-term tenants gained protection on 10-21-2025 when New Rochelle opted into New York's Good Cause Eviction law by Local Law No. 6-2025, codified as Chapter 132, with a high-rent exemption at 345% of Westchester fair market rent and 'small landlord' defined as a landlord of no more than one unit anywhere in New York State.