ADU rules in Seaside Heights

Seaside Heights's Land Use Ordinance (Chapter 246) has no accessory dwelling unit category, and a backyard cottage or garage apartment is a second principal dwelling rather than an accessory building: § 246-5 defines the principal building as the one housing the main use of the lot, 'to which all other buildings and structures on the lot are accessory,' and an accessory building as one whose use is 'customarily incidental' to it. The Planning Board, which sits as the borough's joint Land Use Board, treats a second detached dwelling on a lot as a use the zones do not allow: on 3-2-2026 it granted a d(1) use variance 'for two principal structures on one lot' to keep a house and a detached garage with a second-floor apartment at 211 Sampson Avenue (Application 2025-06, a lot mostly in the Low-Density Residential Zone, where two-family homes are permitted), and Application 2026-06 (210 Blaine Avenue, workshop 10-5-2026) seeks the same relief to keep a front house and a rear two-unit building. The Single-Family Zone permits only 'Single-family dwelling units and accessory building and uses normally auxiliary thereto' (§ 246-37A), every zone's use list is exclusive (§§ 246-3A, 246-36A, 246-38A, 246-39C), and § 127-3 bars residential use of any mobile structure, which rules out a tiny house on wheels.

No district has an accessory or subordinate unit inside or attached to a house; the code's only 'accessory apartments' text is the borrowed state definition in the Fourth Round affordable housing article (§ 246-96, Ord. No. 2026-06), which grants no zoning right and backs no program. A second unit inside a house instead makes it a two-family dwelling, a permitted principal use in most of the borough: the Residential Zone permits 'Single-, two-family and multifamily residential dwelling units' (§ 246-36A(1)), the Retail Business and Resort Recreational Zones adopt that list (§§ 246-39A(1), 246-40A(1), 246-41), Resort Recreational Zone B repeats it (§ 246-41.1A(1)), and the Low-Density Residential Zone permits 'Single- or two-family residential dwelling units' (§ 246-38A(1)). Lot size is the gate: the LDR requires 2,000 sq ft 'for each dwelling unit' (§ 246-38C), so a two-family needs 4,000 sq ft (on 3-2-2026 the Board granted a lot-area variance for a two-family on a 2,500 sq ft lot at 213 Webster Avenue), while the Residential Zone sets 2,000 sq ft for a single-family dwelling and 1,200 sq ft per unit for multifamily dwellings (§ 246-36B(2)), which the borough planner reads as 2,400 sq ft for a two-family home. That is a two-family dwelling, not an ADU, and the Single-Family Zone, where a house is 'designed to provide living facilities, including kitchen, for one family only' (§ 246-5), allows none. Ground-level apartments under elevated houses are also barred in the flood hazard area, which covers almost the whole borough: enclosed space below the lowest floor may be used 'solely for parking of vehicles, building access, or storage' (§ 99-15.2A(5) and B(5)).

Chapter 246 sets no ADU or accessory-building size cap; the binding envelope is § 246-44 plus the per-zone lot sizes. No dwelling, building or structure may exceed 41 feet measured from the finished curb to the top of the roof beam, except in the Single-Family Zone, where the cap is 27 feet measured from the base flood elevation plus one foot to the roof peak (§ 246-44E(1) and (4), as amended 8-3-2022 by Ord. No. 2022-17). Every building or structure must stay 10 feet from the front line and three feet from the rear and side lines, or two feet from the side lines on residential lots 20 feet wide or less (§ 246-44A(1)(a) to (c)), although § 246-44A(1)(e), added by Ord. No. 2022-17, separately sets a four-foot combined side yard (one foot and three feet) for those narrow lots, a conflict the September 2026 Land Use Element also notes. Lot area works as the density cap: 2,000 sq ft per dwelling unit in the LDR (§ 246-38C), 2,000 sq ft for a single-family dwelling and 1,200 sq ft per multifamily unit in the Residential Zone (§ 246-36B(2)), and 4,000 sq ft with 40 feet of frontage in the Single-Family Zone (§ 246-37C). The base residential zones set no building or impervious coverage limit and no floor-area ratio, and a carport is limited by definition to 400 sq ft (§ 246-5).

Seaside Heights authorizes no ADU, so there is no accessory-unit owner-occupancy rule, and nothing in Chapter 246 conditions a house or a two-family dwelling on the owner living there. Owner residence matters only in the rental chapters: a short-term rental property counts as 'owner-occupied' when the owner lives in it 'or in the principal residential unit with which the STRP is associated on the same lot' (§ 179-5), and the distinction sets the security plan for rentals from April 15 through June 30, which must include a SORA-certified security officer when the property is not owner-occupied (§ 179-6.2A(15)). The rental insurance registry asks rental owners for $500,000 of liability coverage but $300,000 of the owner of 'a multifamily home containing four or fewer units, one of which is owner-occupied' (§ 116-2B and C), and rental registration applies to every rented unit 'regardless of the residency of the owner' (§ 55-5A). Only deed-restricted affordable ownership units must be the buyer's principal residence and may not be leased (§ 246-108C).

§ 246-51Q(6) applies 'in each and every district': apartment houses and condominiums need 'parking spaces for two motor vehicles for every one living unit,' and 'One-family homes shall also require parking spaces for two motor vehicles and two-family homes shall require parking spaces for four motor vehicles' (Ord. No. 2002-18). The Residential Site Improvement Standards govern site improvements for any residential development approval and are 'the maximum that may be required in connection with residential development' (N.J.A.C. 5:21-1.5(a) and (b)); Table 4.4 sets 1.5 spaces for a two-bedroom house, 2.0 for three, 2.5 for four (also the default when bedrooms are not stated) and 3.0 for five, applies those single-family values to each unit of a two-family dwelling, and lets the approving authority count available on-street spaces (N.J.A.C. 5:21-4.14(c) and (f)). The local four-space duplex rule therefore binds only up to the RSIS figure for the units' bedroom counts, and applicants before the Planning Board cite RSIS (3-2-2026, 211 Sampson Avenue). Driveway openings on site-plan lots are capped at 16 feet per 100 feet of frontage (§ 246-51P), the zoning permit required before a certificate of occupancy for anything but a one-family dwelling must show 'Parking availability' (§ 246-92F), and short-term rental guests are limited to one vehicle per four occupants (§ 179-6.2A(11)).

No zone lists an accessory dwelling as a permitted or conditional use (the conditional uses are marine commercial services, rooming houses in the Resort Recreational Zones and adult uses in Zone A), so there is no ADU permit path. Where a second unit is lawful as a two-family or multifamily dwelling, it needs a zoning permit from the Zoning Officer ($150 for a new two-family dwelling, $50 per multifamily unit, § 246-92A), construction and flood permits and a certificate of occupancy, but no site plan, because § 246-50C exempts 'single-family and two-family detached dwelling unit buildings'; since Ord. No. 2026-06 a development fee of 1.5% of the added equalized assessed value is also due 'when an additional dwelling unit is added to an existing residential structure' (§ 246-117C(1)(a)). Anything else (a second principal dwelling on a lot, three or more units in the LDR, any second unit in the Single-Family Zone) needs a d(1) use variance, which the joint Land Use Board (the Planning Board, holding all board of adjustment powers under § 246-24C, with its Class I and Class III members excluded from use variances) may grant 'only by the affirmative vote of at least 2/3 of the full authorized membership of the Board' (§ 246-47A(4)). In 2026 the Board granted one to keep a house and a garage apartment at 211 Sampson Avenue (3-2-2026) and unanimously denied one for two houses plus a four-unit building on a 5,052 sq ft LDR lot at 308-310 Sampson Avenue (Application 2025-11, 5-26-2026).

Rental rules sit outside zoning. Every owner of a rented unit must register it (§§ 55-5 and 55-6, under N.J.S.A. 40:48-2.53 and 46:8-28), and a unit leased on a nontransient basis must pass a Code Official inspection 'prior to every initial occupancy or change of occupancy' and at least annually for an updated certificate of occupancy (§ 55-7A; § 55-3B(1) still says biennially), at $100 per unit (§ 55-3B(2)); only registered occupants may live there, and each occupant over the registered maximum draws a mandatory $1,500 fine (§§ 55-13, 55-15A, 55-17A(2), as amended 6-18-2025 by Ord. No. 2025-18). Rented apartments and cottages also need an annual mercantile license ($21 per unit) backed by a certificate of occupancy issued within the prior 12 months (§ 122-1A and F; operating unlicensed carries $1,500 to $2,000 fines under § 122-9C, Ord. No. 2025-19), owners must file a $500,000 liability insurance certificate by each January 1 for a $50 fee (§§ 116-2, 116-3), and a landlord of a building with four or fewer units can be made to post a $500 to $5,000 bond after two tenant disorderly-conduct convictions within 24 months (§ 179-2). Short-term rentals ('less than 30 consecutive days, up to a cumulative total period not to exceed 180 days in a calendar year,' § 179-5, although the same definition says the unit 'can be rented to short-term renters throughout the licensed period') need a license held by the owner (Ch. 179 Art. II, Ord. No. 2023-20): only condominium units whose bylaws allow it, 'Single-family residences' and 'Multifamily residential dwellings' qualify (§ 179-6.1B, which does not name two-family dwellings), the fees are a $200 application fee, a $500 initial annual license fee and a $100 renewal fee per inspection (§ 179-6), and the owner must show a zoning permit, $500,000 of STR-specific insurance, a 10-occupant cap regardless of bedrooms, one vehicle per four guests, guest lists before each change of occupancy and a spring security plan (§§ 179-5, 179-6.2), with fines of $1,500 to $2,000 per violation per day (§ 179-6.6A, Ord. No. 2025-17). A tenant may not operate or sublet a short-term rental (§ 179-6.4H), no transient rental (90 days or less) may go to anyone under 21 from April 15 to June 30 or under 18 the rest of the year (§§ 55-3D, 179-6.2H and I), and short-term rentals owe a 3% municipal occupancy tax on top of state taxes (§ 110-3B).