Side by side · New Jersey
Compare ADU rules across New Jersey
Flexible on where you build? The same backyard cottage can be routine in one city and impossible in the next. This table puts 21 New Jersey cities side by side so you can shortlist the friendly ones before reading a single ordinance, or narrow it to just the cities you are deciding between. Every value is summarized from the city's own code; open a city's page for the full notes, citations, and fine print.
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| City | Detached ADU | Attached / internal | Max size | Owner occupancy | Extra parking | Approval |
|---|---|---|---|---|---|---|
| Asbury Park | Allowed | The ordinance text is written around ADUs in separate structures: Section 30-75.4.l requires an ADU to be constructed in the rear yard behind the principal building, and the definition requires a separate entrance and fully independent cooking and sanitary facilities. The city's FAQ states Asbury Park will consider an ADU in the main house only if the owner lives in the smaller unit. Two-family homes with both units in the principal building may add an ADU only in a separate structure per Section 30-75.4.u. Section 30-15 (definition), Section 30-75.4.j, l, u (Ord. 2024-6); city ADU FAQFull rules for Asbury Park Ordinance read September 2026 | No fixed square-footage cap. For ADUs in a new structure or an expanded accessory structure, the ADU's floor area and building coverage may not exceed that of the principal use and structure; maximum building height is 20 feet in all districts; minimum of two rooms, one of which must be a bathroom; the ADU counts toward district building and lot coverage limits (affordable or accessible ADUs may exceed permitted building coverage by 5%, combinable to 10%). | Required | Minimum one parking space for the ADU; the space may be allocated within an existing driveway with Planning and Redevelopment Department approval. The ADU may not eliminate or reduce required parking for the principal use, and no additional street curb cut may be built if one already exists (an alley curb cut is allowed). The parking requirement is waived for deed-restricted affordable ADUs. | Permitted use |
| Belmar | ADUs are allowed only as a conditional use, and only by converting an existing accessory dwelling structure (a detached secondary building already containing a dwelling unit) or by demolishing such a structure and replacing it with one newly constructed accessory dwelling structure containing not more than one unit. Existing accessory dwelling structures in all single-family residential zoning districts that contain existing accessory dwelling units are eligible; the ordinance does not authorize a brand-new ADU on a lot that never had an accessory dwelling structure. Ordinance read September 2026 | Not allowed | No floor-area cap stated for converting an existing structure. A newly constructed replacement accessory dwelling structure may not exceed the greater of 650 square feet or the footprint of the demolished structure (excluding garage area), and in no case more than 10 percent of lot area (the Director may allow a deviation of up to 15 percent of that area for a more efficient design). It must be one story, maximum 12 feet from average grade to the eaves; attics and basements are allowed only as non-habitable space. | Not required | None. The ordinance states that no additional parking demand shall be deemed created, and no additional off-street parking shall be required, as a result or condition of the conversion of an accessory dwelling unit. | Creation of an ADU is a conditional use subject to the conditions of § 40-6.14.3 and a site plan application to and approval by the Planning Board, with review of the unit's appearance for consistency with the main dwelling and neighborhood. Separately, § 40-6.14.4(a) says no bulk variances or site plan approvals are required unless the Director of Code Enforcement determines that proposed deviations from the replacement-structure design standards exceed the Director's discretion, in which case relief goes to the Zoning Board of Adjustment by minor site plan application with variances. Ordinance read September 2026 |
| Camden | Not allowed | Not allowed | No ADU allowed at any size; detached accessory buildings are capped at 750 sq ft (or 25% of the rear yard, whichever is smaller) and 10 ft in height | Camden's code sets no owner-occupancy rule for an accessory dwelling unit, because it does not allow one; the field is recorded unknown rather than no so the table does not read as though an ADU exists that you may rent out freely. Nothing in Chapter 870 conditions any residential use on the owner living on site. The nearest owner-related requirements sit outside zoning: § 620-19 requires an owner who does not permanently reside in Camden County to appoint a resident agent, § 620-20 requires every owner, operator or lessor of rented space to register the premises with the Department of Code Enforcement, and Chapter 650 rent control applies by its own definition to 'Owner-occupied one-, two-, three-, or four-family dwellings' (§ 650-1, as amended 2-10-2026 by Ord. No. MC-5610). Camden City Code §§ 620-19, 620-20 and 650-1; Ch. 870 contains no owner-occupancy provisionFull rules for Camden Ordinance read September 2026 | No ADU parking standard exists; a single-family dwelling needs 2 spaces per unit and each unit of any other dwelling needs 1.25 (1 bedroom), 1.75 (2 bedrooms) or 2.00 (3 bedrooms) spaces | There is no ADU permit path in Camden because there is no ADU use, so no permitted or conditional-use classification applies; the field is recorded unknown by the directory's convention for codes with nothing at all. For context, the ministerial layer is the zoning permit: § 870-309B bars anyone from erecting, altering, expanding or converting a building without a zoning permit from the Zoning Officer, and § 870-310 gives the Zoning Officer 10 days to act on a complete application. Site plan review is waived for single-family and two-family construction under § 870-41A(1), so a conforming duplex conversion is a staff-level approval. Anything that is genuinely an accessory dwelling instead needs a use variance under § 870-297E(1)(d)[1], heard by the Zoning Board of Adjustment and requiring five affirmative votes. Camden City Code §§ 870-309, 870-310, 870-41A(1) and 870-297E(1)(d)[1]; N.J.S.A. 40:55D-70(d)Full rules for Camden Ordinance read September 2026 |
| Edison | Not allowed | Not allowed | No ADU size standard exists, because Edison authorizes no accessory dwelling unit. The accessory-building envelope that would bound any backyard structure is 15 feet or 1 1/2 stories, whichever is less, in a residential zone, with all accessory buildings together covering no more than 10% of the lot or 35% of the rear yard, whichever is less, and none in the required front yard. | Not addressed. Because no district authorizes an accessory dwelling, Chapter 37 contains no owner-occupancy condition for one, and the code has no accessory-apartment program that a residency test could attach to. The nearest occupancy rule is a housing-code density limit rather than an ownership test: § 17-1.5a.d allows no more than one family plus two unrelated occupants in a dwelling unit without a rooming-house license. New Jersey has no statewide ADU statute imposing or preempting owner occupancy as of 2026-09-04; S1786, S2680, A3488 and A3710 remain in committee, and the accessory-dwelling-unit definition added to the Fair Housing Act at N.J.S.A. 52:27D-304(n) by P.L. 2024, c.2 is a definition, not a mandate. Code of the Township of Edison § 37-10.2; § 17-1.5a.d (no owner-occupancy provision anywhere in Chapter 37)Full rules for Edison Ordinance read September 2026 | No ADU parking standard exists. The residential minimum is 2 spaces per dwelling unit for a one- or two-family detached dwelling, satisfied by a paved driveway of 350 square feet, so a second unit created by variance would carry its own 2-space requirement. | There is no ADU permit path, because no Edison district lists an accessory dwelling as either a permitted or a conditional use, and the zoning permit that § 37-67.3 requires before any building permit can only be issued for a use that complies with Chapter 37. The sole route is extraordinary relief: a use variance from the Zoning Board of Adjustment under N.J.S.A. 40:55D-70(d), which § 39-7.3a4 authorizes 'in particular cases and for special reasons, but only by the affirmative vote of at least two-thirds (2/3) of the full authorized membership of the Board.' The application fee is $1,000 per use variance (§ 39-12.18d.3) and the escrow deposit $5,000 per d-variance (§ 39-12.23e.1(c)), though § 39-12.23b.2 exempts development of or improvement to one single-family dwelling on an existing lot from escrow, which is why the Township's 2026 Land Use Application notes that single-family home variance applications are escrow-exempt. § 39-12.25 (Ord. No. O.1540-2006) makes a certified shorthand reporter mandatory at the applicant's expense for every development application except minor subdivisions, minor site plans and standalone 'c' variances, so a use variance carries that cost too, and § 39-12.11 lets any applicant or interested party appeal the Board's use-variance decision to the Township Council. This is discretionary relief, not a conditional use, so it is recorded as unknown rather than conditional-use. Code of the Township of Edison § 37-67.3; § 39-7.3a4; § 39-12.18d.3; § 39-12.23e.1(c); § 39-12.25; N.J.S.A. 40:55D-70(d)Full rules for Edison Ordinance read September 2026 |
| Elizabeth | Not allowed | Not allowed | No ADU size standard exists, because the code has no ADU category. The binding cap on a detached backyard structure is the accessory building rule: up to three one-story accessory buildings, total accessory building coverage no more than 33 percent of the principal building coverage, only one of them larger than 100 sq ft or taller than 8 feet, and none exceeding 10 feet in height (a pitched roof may project above that). | The zoning code is silent, because there is no accessory dwelling unit to regulate. No owner-occupancy condition attaches to a two-family dwelling in Schedule IA either. The only owner-occupancy test anywhere in the Elizabeth code sits in short-term rental licensing: Chapter 5.90 defines 'owner-occupied' as the owner residing 'in the short term rental property, or in the principal residential unit with which the property is associated on the same lot', and requires a driver's license, voter registration or state ID proving that address is the owner's principal residence. That is a licensing condition for renting nightly, not a land-use rule about who may occupy a second unit. Ordinance read September 2026 | No ADU-specific requirement exists. Residential parking in Elizabeth is governed by the state Residential Site Improvement Standards (N.J.A.C. 5:21) rather than a local per-unit ratio, so a lawfully added dwelling unit (a two-family conversion where that use is permitted) must supply the RSIS spaces for its bedroom count. | There is no ADU permit path to classify: no district in Schedule IA lists an accessory dwelling as permitted, and Schedule III (Conditional Uses) covers rooming houses, mausoleums, child-care facilities, nursing homes, essential services, gas stations, auto repair, junkyards, resident parking, gas tanks, guest retail and bakeries, helistops, amusement machine complexes, community residences and billboards, with no accessory dwelling standard. In practice a homeowner faces two real routes. Where Schedule IA already permits a two-family dwelling (R-2, R-2C, R-3, R-3A, R-4, C-1, C-2), the conversion is administrative: a zoning permit under 17.08.065, a construction permit, and a new certificate of occupancy on change of use under 17.08.080. Anywhere the use is not listed, including all of R-1, it takes a use variance from the Zoning Board of Adjustment under N.J.S.A. 40:55D-70(d), a discretionary hearing needing five affirmative votes. Schedule IA; Schedule III; § 17.08.065; § 17.08.080; § 17.16 (Zoning Board of Adjustment)Full rules for Elizabeth Ordinance read September 2026 |
| Hoboken | Not allowed | Not allowed | Not specified; no ADU size standard exists because the code has no ADU provisions. For the one Court Street garage-apartment situation in R-1, the accessory building may measure 30 feet above average grade and may not exceed one dwelling over grade-level parking; through lots there are limited to 20% lot coverage for the Court-Street-fronting building. | Not addressed anywhere in the code. Because Hoboken has no ADU authorization, no owner occupancy standard for accessory units exists; the accessory apartment definition and the Court Street provision are silent on occupancy, and a full-text search of the code for 'owner occupancy' returns zero results. Ordinance read September 2026 | No ADU-specific standard exists. Residential buildings require no off-street parking for the first 5 dwelling units and 1 space per dwelling unit after the first 5. A conversion that adds a dwelling unit must meet the off-street parking requirement for the new use before a new certificate of occupancy issues. In the R-1 district, off-street parking for residential use is neither permitted nor required, new or existing. | There is no ADU permit path because no district lists an accessory dwelling as a permitted or conditional use. Accessory uses in the R districts are limited to items such as private garages, home occupations, signs, wireless antennas, and 'other uses customarily incidental to principal uses'; the conditional use article (§§ 196-36 to 196-38) contains no accessory dwelling standard in any of its subsections A through DD. Adding a unit as a conversion to a permitted residential use requires meeting all requirements for the new use plus a new certificate of occupancy from the Zoning Officer. Ordinance read September 2026 |
| Jersey City | Allowed | Not allowed | No square footage cap; size limited by accessory building standards: maximum height 18 feet (and two stories in RH-2, R-1, and R-2), side yard setback 2 feet (3 feet in R-2), and lot coverage limits (R-1 allows an extra 5% lot coverage when an ADU is present) | Not required | None in RH-1, RH-2, and R-1, where ADUs are expressly exempt from any minimum parking requirement; in R-2 the general residential standard applies (0.3 spaces per bedroom on lots wider than 50 feet; off-street parking is prohibited on lots 50 feet wide or less) | Permitted use |
| Lakewood | Not allowed | An internal accessory unit is allowed as of right, but in one form only. Section 18-910D makes basement apartments permitted uses in all residential zones, and section 18-910I prohibits them in the A-1 Agricultural Zone and in age-restricted communities. Section 18-910C requires the unit to be 'solely contained beneath the ground floor and separate from the residence above the ground floor', with its own USPS-recognized address and mailbox plus a kitchen, bathroom, bedroom and living area, and section 18-910E allows only one per single-family residence, including townhouses and condominiums. Above-grade attached forms (an addition, an attic or over-garage conversion, an in-law wing) are authorized by no section and would need a use variance. Construction conditions are real but ministerial: an independent means of entry and exit plus a secondary egress window or door, access to all utility meters and shutoffs, a fire separation system with smoke and carbon monoxide detectors, and full compliance with the state Uniform Construction Code. Ordinance read September 2026 | No square-footage or percentage cap. The unit must fit entirely beneath the ground floor of the house, so the basement footprint is the practical limit, and only one basement apartment is allowed per single-family residence. | Not required | No spaces required for the apartment as such, but section 18-807A.1 counts a basement as two bedrooms when computing the house's parking, which usually adds about one space. | Permitted use |
| Maplewood | Allowed | Allowed | No more than 40% of the living area of the principal dwelling unit, no more than 800 sq ft, no less than 300 sq ft, and no more than two bedrooms; a fully handicapped-accessible ADU (NJ Barrier Free Subcode) earns a 5% increase in total maximum floor area, applicable to the principal dwelling, the ADU, or both | Required | No ADU-specific parking requirement; the exhaustive condition list in § 271-90 contains no parking standard | Permitted use |
| Montclair | Allowed | Allowed | Living area no more than 40% of the habitable area of the principal building, up to a maximum of 800 sq ft, and no less than 300 sq ft; no more than three rooms excluding kitchen and bathroom. Adaptive reuse ADUs that are fully accessible under the NJ Barrier Free Subcode get a 5% floor area bonus. Detached ADUs may not exceed 40 feet in length or width in any one direction. | Required | At least one off-street parking space must be provided for an ADU. | Permitted use |
| Newark | ADUs (detached or attached to the principal residence, one per property) are listed as a conditionally permitted accessory use only in the R-1 Detached Single-Family Residential district in Table 4-1; the row shows C for R-1 and a dash (not permitted) for R-2 through R-6, and ADUs appear in no other district use table. Conditional uses require an application to the Central Planning Board under MLUL Section 54 procedures. Detached ADUs must meet bulk standards: max 20 feet height, minimum 20% primary facade transparency, setbacks of 10 feet from one side and 5 feet from the other, 5 feet from rear line, principal building, and other accessory structures, and may not be located in the front yard beyond the principal building's front facade. Ordinance read September 2026 | Section 41:6-2-1 allows one ADU per property, detached or attached to the principal residence, as a conditional use in R-1 only. However, an ADU shall not be permitted in a basement, cellar, or attic, and conversion of an existing garage into an ADU is prohibited, which rules out the most common internal-conversion forms. Ordinance read September 2026 | Maximum 600 sq ft floor area; minimum floor area is 400 sq ft or 25% of the principal dwelling's floor area. Detached ADUs may not exceed 20 feet in height. | Required | One off-street parking space required for the ADU. | ADUs are a conditional use: Table 4-1 marks them C (conditionally permitted) in R-1, and the standards sit in Chapter 41:6 Conditional Use Standards. Section 41:6-1 requires an application to the Central Planning Board, heard under the procedures of Section 54 of the NJ Municipal Land Use Law (C.40:55D-67); the Board may deny a conditional use it judges detrimental to health, safety, and general welfare. Ordinance read September 2026 |
| North Wildwood | Not allowed | Accessory apartments (a single additional dwelling unit within a single-family detached dwelling, per the § 276-7 definition) are allowed only as conditional uses, and only in three zoning districts: R-1.5 Single-Family Residential (§ 276-15.1C(1), amended 10-17-2023 by Ord. No. 1916), MC-1 Motel Commercial 1 (§ 276-24E(1)), and MC-2 Motel Commercial 2 (§ 276-24.1E(1)). In each district they may be developed as an optional development scheme subject to enumerated standards: located inside the single-family detached dwelling, no studio apartments, one per lot, entrance on the front elevation or the front third of a side elevation, RSIS parking compliance, and ADA plus N.J.A.C. 5:94-3.14 accessibility and adaptability compliance. A full-text search of the code found no other district that lists accessory apartments. Ordinance read September 2026 | In the R-1.5 district, no larger than 25% of the total habitable floor area of the structure (§ 276-15.1C(1)(d)); in the MC-1 and MC-2 districts, no larger than 40% of the net habitable floor area of the single-family detached dwelling (§ 276-24E(1)(d), § 276-24.1E(1)(d)). All districts require at least the minimum net habitable floor area set by the city's Affordable Housing Ordinance whether or not the unit is an affordable unit. The § 276-7 definition separately caps accessory apartment units at 25% of the net habitable floor area of the principal dwelling and sets a 500 square foot minimum with at least two rooms; studio apartments are prohibited in every district. | Not required | Any increase in the number of bedrooms on the lot caused by adding an accessory apartment to an existing single-family detached dwelling requires compliance with the parking requirements of the New Jersey Residential Site Improvement Standards, RSIS (N.J.A.C. 5:21-1 et seq.). RSIS sets parking by bedroom count; § 276-15.1G(1) adds that if the applicant does not specify bedroom counts, each dwelling unit is charged at the RSIS four-bedroom rate. Stacked parking is limited (§ 276-15.1G(3)). | Accessory apartments are expressly listed under the heading 'Conditional uses permitted' in R-1.5 and 'Permitted conditional uses' in MC-1 and MC-2, and the R-1.5 purpose statement says the district exists 'to permit accessory apartments as a conditional use.' Conditional use approval in New Jersey runs through the planning board under N.J.S.A. 40:55D-67 (the statute the ordinance cites for its other conditional uses). Ordinance read September 2026 |
| Ocean City | A detached accessory apartment is possible, but only through the city's deed-restricted affordable housing program. Section 25-211.1 covers voluntary conversion of existing single family or two family dwellings or accessory buildings, and section 25-211.2 extends eligibility to owners who occupy the principal structure on a lot where an accessory unit will be located. The affordable housing rewrite adopted 5-7-2026 added a definition at section 25-2000.2 that expressly reaches a unit constructed as a separate detached structure on the same lot and says accessory apartments are also called accessory dwelling units. The older zoning definition at section 25-107 is narrower, describing only a converted portion of an existing dwelling or an existing accessory building, so a brand-new detached building is not clearly authorized. Either way the unit is allowed only in the R-2 and RMF zone districts, never on bayfront or oceanfront lots, and only on fully conforming lots. Ordinance read September 2026 | Converting an existing single family or two family dwelling to hold an accessory apartment is the core of the program, and the 2026 definition at section 25-2000.2 confirms that the unit may sit inside the primary dwelling or be built as an extension of it. It is open only to owner-occupants who rent the unit to low- or moderate-income households, and only in the R-2 and RMF zones away from the bayfront and oceanfront. The accessory apartment and any existing unit must each have a separate door with direct access to the outside, and the work may not add a door to the front facade of the principal structure. Ordinance read September 2026 | 950 square feet gross floor area maximum, 450 square feet minimum. The unit must contain one kitchen with sink, refrigerator, and cooking facilities and one full bathroom with sink, toilet, and tub or shower. | Required | Yes. Accessory apartments created by new construction must conform to the parking requirements of the zone district (R-2 or RMF); accessory apartments created through renovation or rehabilitation of existing structures must add one additional off-street parking space. All spaces must comply with the ordinance parking standards. | Permitted use |
| Paterson | Not allowed | Not allowed | No ADU size standard exists, because no accessory dwelling is allowed. Nearest limits: an accessory building in a residential zone is capped at 500 sq ft of floor or ground area or 1/3 of the principal building's first-floor ground area, whichever is less, and 15 feet in height, and may not be used for human habitation. | No owner-occupancy standard for accessory units exists, because the ordinance authorizes no accessory dwelling unit to attach one to. Owner occupancy does carry weight elsewhere in Paterson's rental law, and a homeowner adding a lawful second unit will meet it in three places: § 175-2 excludes from 'housing space' a two-family dwelling in which the owner occupies one unit and rents the other, so an owner-occupied two-family needs no certificate of re-rental approval on turnover; § 381-3E applies rent leveling to owner-occupied dwellings only at three or more units, against two or more when the dwelling is not owner-occupied; and § 275-18A exempts an owner-occupied home where the owner is present from the Eastside unattended short-term-rental ban. Ordinance read September 2026 | No ADU parking standard exists. A unit added lawfully as part of a one or two family dwelling is parked as a full dwelling unit: 1.5 spaces for a 2-bedroom unit, 2.0 for 3 bedrooms, 2.5 for 4 and 3.0 for 5. | There is no ADU permit path at all. Every use needs a Zoning Permit from the Zoning Officer under § 300-1.1.A before any construction permit or certificate of occupancy issues, and § 300-1.3.C directs that a Zoning Permit application for a use not specifically listed as permitted in a particular zone district shall be denied, with the Zoning Officer stating what approvals or variances would be needed. For an accessory dwelling that means a use variance from the Zoning Board of Adjustment under § 200-2.2.D, the local restatement of N.J.S.A. 40:55D-70(d), which requires special reasons, a showing of no substantial detriment to the public good under § 200-2.2.F, and five affirmative votes. The § 300-3.1 fee schedule prices a residential use variance at $500 plus escrow of $1,000 for lots under 3,000 sq ft or $2,500 at or above that. By contrast, converting to a two-family dwelling where the zone permits it is an ordinary administrative Zoning Permit, with Planning Board site plan review only if otherwise triggered. Ordinance read September 2026 |
| Princeton | Allowed | Allowed | 800 sq ft or 25 percent of the total floor area of the principal dwelling, whichever is greater; ADUs deed-restricted to low- and moderate-income occupancy under UHAC may reach 1,000 sq ft or 30 percent, whichever is greater; a fully barrier-free accessible ADU earns the property a 5 percent increase in total maximum floor area; maximum three habitable rooms (four for UHAC-restricted units); a detached ADU structure may not exceed the size of the principal dwelling | Not required | No additional off-street parking for ADUs with two habitable rooms; one additional off-street space for ADUs with three habitable rooms; the ADU may not eliminate the required parking for the principal single-family dwelling | Permitted use |
| South Orange | Allowed | Allowed | 350 to 750 square feet; must have less total square footage than the principal dwelling; maximum two bedrooms; capped at 25 feet in height; accessory structures may not occupy more than 30% of the rear yard area | Required | One additional off-street space per ADU, on top of the parking required for the principal dwelling | Permitted use |
| Teaneck | Allowed | Allowed | Attached ADU: up to 40% of the primary dwelling's floor area or 800 sq ft, whichever is greater; if deed-restricted for low- and moderate-income occupancy under UHAC (N.J.A.C. 5:80-26.1 et seq.), up to 50% of the primary dwelling's floor area or 1,200 sq ft, whichever is greater. A fully handicapped-accessible ADU (NJ Barrier Free Subcode) earns the property a 5% increase in total maximum floor area, applicable to the PDU, the ADU, or both. Detached ADUs are capped at 24 feet in height; the ordinance's square-footage formula in Sec. 33-56(e) is worded for attached ADUs, and a garage attached to a detached ADU may not exceed the allowable combined square footages otherwise allowed on the lot. | Required | One parking space per ADU; the space must be located within the setbacks and in an existing driveway as tandem parking. | Permitted use |
| Toms River | Not allowed | An accessory apartment inside a detached, owner-occupied single-family dwelling is permitted, but only in the R-800, RR, R-400C and R-400 zoning districts, only on a lot that otherwise conforms to the district's bulk requirements, and only as a deed-restricted affordable unit rented to a low- or moderate-income household. The townwide program is capped at 10 units. The apartment must be self-contained, with a kitchen, complete sanitary facilities, sleeping quarters and a private entrance, must have its own separate door, and must consist of at least two rooms, one of which is a full bathroom. Ordinance read September 2026 | No fixed square-footage cap; the accessory apartment may not exceed the gross floor area of the existing principal dwelling on the lot. Minimum size is two rooms, one of which must be a full bathroom. The Township may not restrict the number of bedrooms. | Required | Minimum of two on-site parking spaces provided exclusively for the accessory apartment, in addition to the spaces required for the existing principal dwelling. | Permitted use |
| Trenton | Trenton's Land Development Ordinance allows a detached ADU as an accessory use with no district restriction of its own, but only where two objective gates are met: § 315-9.4.B(1) allows an ADU only on a lot with one single-family dwelling, and § 315-9.4.B(3) requires the lot to have a minimum area of 4,000 square feet. Single-family dwellings are a permitted use only in the seven residential districts (RL-1, RL-2, RL-3, RM-1, RM-2, RH-1, RH-2) under Table 8-1, so no ADU is possible on a two-family, rowhouse or multi-family lot, or in a commercial or industrial district. The 4,000 square foot floor is the gate that bites: RL-3's own minimum lot area is 4,000 square feet and RL-1's and RL-2's are larger, but a conforming single-family lot in RM-1, RM-2, RH-1 or RH-2 can be as small as 2,500 square feet (Table 4-1), which excludes much of Trenton's rowhouse fabric absent a C variance. A detached ADU must sit three feet from an interior side lot line and ten feet from a rear lot line, and is barred from the front yard and the corner side yard unless it is built inside a detached garage. § 315-9.4.B(1), (3), (5), (6) and § 315-2.3 (definition); Table 8-1 (§ 315-8.2) and Table 4-1 (§ 315-4.3); Ord. No. 23-70, adopted 12-21-2023Full rules for Trenton Ordinance read September 2026 | The same section covers interior and attached ADUs: § 315-9.4.B(5) states the ADU may be within, attached to, or detached from the primary dwelling structure and may be part of a detached accessory structure, and may be developed within an existing structure or as new development. So a basement, attic, or addition conversion is on exactly the same footing as a backyard cottage. The identical gates apply: one single-family dwelling on the lot, a lot of at least 4,000 square feet, one ADU per lot, and the design rule at § 315-9.4.B(9) that the primary structure must still read as a house with the ADU entrance unobtrusive from the view that shows the principal entrance. Note that an internal ADU is not the same thing as a residential conversion under § 315-4.5, which turns a single-family dwelling into two or more units, needs Planning Board conditional use approval, and carries its own 2,000 square foot existing-house minimum, per-unit floor area minimums and a one-space-per-new-unit parking requirement. § 315-9.4.B(1), (3), (4), (5), (9); contrast § 315-4.5 (single-family dwelling conversions); Ord. No. 23-70, adopted 12-21-2023Full rules for Trenton Ordinance read September 2026 | 800 sq ft of gross floor area, and in no case more than 40% of the primary dwelling's floor area or more than 2 bedrooms. A detached ADU is additionally capped at 20 feet in height, its footprint cannot exceed the principal building's footprint, and it counts toward district building and impervious coverage limits. | Required | None. § 315-9.4.B(10) states plainly that no additional parking is required for the ADU, and Trenton abolished off-street parking minimums citywide. | Permitted use |
| Wildwood | Not allowed | One additional dwelling unit may be created as an accessory apartment inside a single-family dwelling in any of Wildwood's four residential zoning districts: R-1 Low Density Residential, R-2 Moderate Density Residential, RM Residential Multifamily, and WR Waterfront Residential. Each of the four lists "Accessory apartment units within detached single-family dwellings, subject to § 17-503 and the bulk requirements below and herein" among its permitted accessory buildings and uses. Read section 17-503A's district list with care: it still names R-3, WR-1 and MC-R, but those districts no longer exist. Section 17-401, as amended 3-22-2023 by Ord. No. 1254-23, establishes only R-1, R-2, RM and WR as residential districts, and the Zoning Map adopted the same day carries only those four in its legend. Section 17-201 defines the unit as "a single additional dwelling unit within a single-family detached dwelling which shall contain at least two rooms and have sanitary and cooking facilities for the exclusive use of its occupant." § 17-503A; § 17-401; § 17-412B(4)(a), C(4)(a), D(4)(a), E(4)(a); § 17-201 (definition of ACCESSORY APARTMENT UNITS (IN-LAW SUITE))Full rules for Wildwood Ordinance read September 2026 | No larger than 25% of the net habitable floor area of the dwelling unit, with a minimum of 500 square feet; must contain at least two rooms | Not required | Per the § 17-608 off-street parking schedule, accessory apartments require, for each dwelling unit: 1.0 space for 1 bedroom, 1.5 spaces for 2 bedrooms, 2.0 spaces for 3 bedrooms | Which approval you need depends on whether the house has to grow. All four residential districts list accessory apartment units among their permitted accessory buildings and uses rather than among their conditional uses, so an apartment carved out of the existing single-family house is treated as an accessory use that must meet the section 17-503 standards. Section 17-503H adds a conditional use step for the other case: "Before a construction permit or certificate of occupancy shall be issued for any creation of an apartment involving the enlargement of an existing dwelling, application shall be made to the Planning Board for a conditional use as permitted by this chapter," and that review includes any required site plan review. Treat the Planning Board route as the default in practice: section 17-503 is codified inside "Section 500. Conditional Uses and Supplemental Regulations," and the City's own adopted Fourth Round Housing Element and Fair Share Plan describes accessory dwelling units as permitted on a lot "which meets all the conditional requirements of the ordinance." Ask Wildwood's Zoning Officer which track applies before assuming an interior conversion avoids a Planning Board hearing. Ordinance read September 2026 |
| Woodbridge | Not allowed | Not allowed | No ADU size standard exists, because no accessory dwelling unit is permitted. Detached accessory buildings are capped at 15 feet in height (tool and equipment sheds at 150 square feet and 10 feet) and may not contain a dwelling unit. | Not addressed anywhere in Chapter 150. Because Woodbridge authorizes no accessory dwelling unit, there is no owner-occupancy standard for accessory units to report: the residential district sections (§§ 150-25 through 150-31), the general residential regulations at § 150-24B and the 22 conditional-use standards at § 150-44 all set permitted uses and bulk limits without conditioning any dwelling on the owner living there. If the Zoning Board of Adjustment ever granted a use variance for a second unit under § 150-9I(4), it could attach owner occupancy as a condition of that one approval, but that would be case-specific relief, not an ordinance rule. Separately, the Township's rental chapter reaches any house let to anyone but the record owner: § 17-9.2 applies to all residential dwellings including single-family houses offered for lease to persons other than the record owner, whether or not rent is paid. Land Use and Development Ordinance Ch. 150 (no owner-occupancy provision); Revised General Ordinances § 17-9.2Full rules for Woodbridge Ordinance read September 2026 | No ADU parking rule exists. Residential off-street parking follows the state Residential Site Improvement Standards (N.J.A.C. 5:21), which set spaces by unit type and bedroom count. | There is no ADU permit path, because no Woodbridge district lists an accessory dwelling as a permitted or a conditional use. The conditional-use article, § 150-44, enumerates 22 categories (government buildings, places of worship, drive-through eating establishments, public utilities, nurseries, automotive uses, quasi-public uses, community residences for the developmentally disabled, hotels and motels, cannabis businesses and others) and none of them is an accessory or second dwelling. Ordinary residential work runs through the Construction Official and a zoning permit under §§ 150-5 and 150-7, although § 150-7A exempts "the use, reuse or sale of single-family residential dwellings" from the zoning permit itself. The only route to a second unit on a one-family lot is a use variance from the Zoning Board of Adjustment under § 150-9I(4), Woodbridge's codification of N.J.S.A. 40:55D-70(d), which requires the affirmative vote of at least five of the Board's full authorized membership; the Board may grant any accompanying site plan or conditional use approval under § 150-9J. Land Use and Development Ordinance § 150-44; §§ 150-5, 150-7A; § 150-9I(4) and JFull rules for Woodbridge Ordinance read September 2026 |
Summarized from each city's ordinance text, most recently read September 2026. Tap a value marked with an info icon to see exactly what it depends on, straight from the ordinance. Nearly every value has zone, lot-size, or process caveats beyond that; the per-city pages carry the full notes and code citations. Treat this as orientation, not a permit determination.
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Reading the table
- Detached ADU is the make-or-break column for backyard cottages: minimum lot sizes (often 8,000 to 14,500 sq ft) hide behind many of the "Allowed" values, so check your lot before celebrating.
- Attached / internal (basement apartments, additions) is legal almost everywhere and is usually the path of least resistance.
- Approval: "Permitted use" means staff-level sign-off; "Conditional use" means a public hearing, which adds time, cost, and uncertainty.
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