Building an ADU in New Jersey

New Jersey has no statewide ADU law

No New Jersey law in force today makes towns allow ADUs. The bill that would do so, S1786, is still pending in the Legislature. Your municipality's zoning ordinance decides whether you can add a backyard cottage, a basement or attic apartment, or a unit over the garage.

Under the Municipal Land Use Law, a town's governing body "may adopt or amend a zoning ordinance relating to the nature and extent of the uses of land and of buildings and structures thereon." A zoning ordinance may regulate "the bulk, height, number of stories, orientation, and size of buildings," how much of a lot structures may cover, and minimum lot sizes. Those powers are where local ADU rules come from, so the rules differ from town to town.

Start with your town's zoning officer or planning office. Ask whether the zoning ordinance lists an "accessory dwelling unit," "accessory apartment" or similar use in your zone. [1][3][4]

The pending bill: S1786 and A3567

S1786, sponsored by Senators Troy Singleton and Britnee Timberlake, "Concerns development of accessory dwelling units and related regulations." It was introduced January 13, 2026. On June 1, 2026 the Senate Community and Urban Affairs Committee reported it with amendments (3 yes, 2 no), and it was referred to the Senate Budget and Appropriations Committee. Its Assembly twin, A3567, has sat in the Assembly Housing Committee since January 13, 2026. A separate Assembly ADU bill, A3488, is also in that committee. None of them is law.

As amended in committee, S1786 would:

• bar town ordinances from prohibiting or restricting a complying ADU in towns with fewer than 9,000 people per square mile, and in denser towns that already allow ADUs;
• not apply to a town whose ordinance allowing ADUs took effect on or before January 1, 2025 and is still in effect;
• give towns 90 days to adopt an ADU ordinance;
• allow an ADU on a lot where a single-family or two-family home is a permitted use;
• cap ADU height at the height of the main home and require at least five feet from the lot line;
• bar extra off-street parking requirements;
• bar renting an ADU built after the law for less than 30 days;
• make approval a ministerial action without a public hearing, with a written decision within 60 days of a complete application, or the application is deemed approved;
• let applicants appeal a denial or conditions to the Commissioner of Community Affairs;
• cap the utility connection fee for a detached ADU at half the fee for a new main home, and bar new connections or fees for an ADU inside or attached to an existing home (unless built with a new home);
• bar a certificate of occupancy for the ADU before the main home has one.

The Legislature's fiscal estimate (July 16, 2026) says the bill's effect on town and state costs and revenues is indeterminate. If S1786 passes, these rules would change; until then they do not apply. [1][2][6][7][8][9]

The earlier bill that stalled: S2347 (2024-2025)

The same sponsors' 2024-2025 bill, S2347, carried the same title. A Senate committee reported it as a substitute on February 15, 2024, and the Senate amended it on June 2, 2025, but it remained at second reading in the Senate and did not become law. S1786 is its successor in the 2026-2027 session. [1][10]

ADUs and New Jersey's affordable housing (Mount Laurel) law

New Jersey's Fair Housing Act responds to the Mount Laurel rulings, under which every municipality in a growth area must provide "a realistic opportunity for a fair share" of its region's need for low- and moderate-income housing. As amended in 2024 (P.L.2024, c.2), the Act defines an "accessory dwelling unit" as a unit with "complete independent living facilities with a private entrance," including a stove and refrigerator, located inside or attached to a home, in an accessory structure, or in a separate detached building on the same lot.

The Act lists "Creation of accessory dwelling units to be occupied by low- and moderate-income households" as one use of the state's New Jersey Affordable Housing Trust Fund. The Department of Community Affairs (DCA) rules at N.J.A.C. 5:99, which took effect December 15, 2025, also list "Accessory dwelling units" among the housing activities a town may pay for from its own affordable housing trust fund.

Whether a particular ADU counts toward a town's fair share depends on the town's approved housing plan and the affordability rules. Some towns allow larger ADUs if they are deed-restricted as affordable (see Teaneck below). Ask your town's planning office. DCA takes Fair Housing Act questions at AHMS@dca.nj.gov. [5][11][12][13][14][15][16]

State programs

DCA's NJHOMES Launchpad program is for municipalities. In August 2025 DCA picked ten municipalities (East Amwell, East Orange, Evesham, Fairfield, Far Hills, Mendham, Montclair, Palisades Park, Salem and Stafford) as its first cohort, for training, technical help and funding. DCA said ADUs were "a priority innovation to be explored" and that more than half of the towns will include them in their plans.

If your town is building an ADU program, ask its housing office whether it offers help to homeowners. See our ADU grants guide and ADU financing guide for other options. [17]

Building code and permits

New Jersey's building code is the Uniform Construction Code (N.J.A.C. 5:23), published by DCA's Division of Codes and Standards. Your town's construction official handles permits. The code makes it unlawful to "construct, enlarge, repair, renovate, alter, reconstruct or demolish a structure, or change the use of a building" without first applying to the construction official and getting the required permit.

DCA publishes the standard construction permit application forms (form F100 plus building, electrical, plumbing and fire technical sections), which you file with your local construction code office. For code questions, DCA's Code Assistance Unit is at (609) 984-7609 or CodeAssist@dca.nj.gov. [18][19][20][21]

If your town's zoning doesn't allow it

Under the Municipal Land Use Law, the zoning board of adjustment hears appeals of zoning decisions and can grant variances. A variance under subsection d. of the law, which covers allowing "a use or principal structure in a district restricted against such use or principal structure," needs "special reasons" and at least five votes on a municipal board. No variance may be granted without showing it causes no "substantial detriment to the public good" and does not "substantially impair the intent and the purpose of the zone plan and zoning ordinance." Ask your zoning officer which kind of approval your plan needs. [22]

Related state rules: renting a room and tiny homes

Under N.J.S.A. 40:55D-68.4 and 40:55D-68.5 (P.L.1997, c.339), a town may not stop a senior citizen (62 or older, or a qualifying spouse) who owns a single-family home as a primary residence from renting a room or rooms in it to one person. Towns may allow more than one. That law is about renting rooms inside the home, not a separate unit.

A 2019 law (P.L.2019, c.490, N.J.S.A. 40:55D-66.17) lets a town adopt a tiny home rental ordinance to lease vacant town-owned land for tiny homes, defined as "400 square feet or less in floor area excluding lofts." It covers town-owned lots, not tiny homes in your backyard. See our tiny house guide. [23][24][25]

Example: Teaneck's ADU ordinance

Teaneck adopted an ADU article (Ord. No. 6-2025, February 11, 2025; parts were amended by Ord. No. 32-2025, September 9, 2025). Its code allows ADUs "in the R-S, R-M, and B-R zones as a permitted use," with conditions including:

• only with a detached single-family home, and one ADU per lot;
• the owner must live in the ADU or the main home;
• an attached ADU may be up to 40% of the main home's floor area or 800 sq ft, whichever is greater (50% or 1,200 sq ft if deed-restricted as affordable);
• detached ADUs up to 24 feet high, with 4-foot side and rear setbacks for new ADUs;
• one parking space, as tandem parking in an existing driveway;
• no separate street-facing entrance, and no balconies or decks.

Other New Jersey towns have different rules or none. Check your own town's code. [5]

What to check with your town

Because the rules are local, ask your zoning officer or planning office:

• Whether your zone allows an ADU or accessory apartment, and on what lot types.
• The maximum size, height and setbacks.
• Whether the owner must live on the property.
• How many parking spaces you need.
• Whether short-term rentals are allowed.
• Whether an affordable (deed-restricted) ADU gets different rules.
• Which approvals you need: a zoning permit, a variance, and a construction permit.

Our ADU permit process guide, basement apartment guide, garage conversion guide and ADU cost guide cover the general steps. [4][18]

New Jersey laws to know

• Municipal Land Use Law, N.J.S.A. 40:55D-62 and 40:55D-65

  Lets each town's governing body adopt a zoning ordinance regulating land uses and the size, height and bulk of buildings, which is where local ADU rules come from. [3][4]

• Fair Housing Act, N.J.S.A. 52:27D-304 and 52:27D-320

  Defines an accessory dwelling unit and lists creating ADUs for low- and moderate-income households as a use of the state's affordable housing trust fund. [12][13]

• S1786 / A3567 (2026-2027), proposed ADU law (pending)

  As amended in a Senate committee, S1786 would make ADUs a permitted use in many towns, with ministerial approval, a 60-day decision deadline, no added parking and a 30-day minimum rental; neither bill has passed either house. [1][6][8]

• N.J.A.C. 5:23, Uniform Construction Code

  The statewide building code: you need a construction permit from your town's construction official before you build, enlarge or alter a structure. [18][19]

Questions people ask