Rental conversions in Central Jersey

New Jersey's Division of Codes and Standards has noted that some local zoning boards now approve accessory dwelling units, letting properties zoned only for one- or two-family houses add another unit.⁶ As introduced, S1786 would permit accessory dwelling units on property zoned for one- or two-family homes and have each town adopt one of two model ADU ordinances.¹³ A state bill on accessory dwelling units, S1786, was introduced in the Senate on January 13, 2026, reported from committee with amendments on June 1, 2026, and sent to the Senate Budget and Appropriations Committee.¹⁴ The Assembly version of the state accessory dwelling unit bill, A3567, identical to S1786, was introduced on January 13, 2026 and referred to the Assembly Housing Committee.¹⁵

Until one of those bills becomes law, the answer for a Middlesex address sits in the municipal zoning ordinance. Bring your block and lot to the zoning officer, ask whether an accessory apartment is allowed in your zone and on what parking and owner-occupancy terms, and get the answer in writing before hiring an architect.

Some owners picture a converted lower level as a short-term rental instead. Towns can regulate that separately from apartments. East Brunswick prohibits renting a home to guests for stays of less than 30 consecutive days.¹⁶ In East Brunswick, a permitted short-term rental of one unit in a two-family house is allowed only when the owner lives in the other unit as a principal residence, and a single-family house qualifies only if one of its owners lives there.¹⁶ An East Brunswick owner must get a short-term rental permit from the township's Department of Planning and Engineering before renting or advertising a short-term rental.¹⁶

Check whether your own town has a similar chapter before listing a unit for stays of weeks rather than a lease of months.

In one- and two-family houses, work that creates an additional dwelling unit must separate the new unit from the existing one with fire partitions or horizontal assemblies.¹⁰ For a lower-level unit in a raised ranch, most of that separation is overhead: the ceiling under the main floor and the door at the inside stair. Have both detailed on the drawings before pricing.

When an alteration creates a bedroom below the fourth floor, it needs a window or exterior door that meets the subcode's escape-opening requirements, plus a hard-wired smoke alarm in the bedroom and a second one near it.¹⁰ The 2021 IRC requires at least one egress door for each dwelling unit, reached by a continuous path that does not pass through a garage, and opening to a public way or a yard or court that leads to one.¹⁷ Routing the tenant's only way out through the garage or the owner's kitchen fails that test.

If the new unit is on the lower level in Highland Park, North Brunswick or Piscataway, test for radon before anyone signs a lease. NJDEP rates three Middlesex County municipalities Tier 1, its high radon potential category: Highland Park, North Brunswick and Piscataway.¹⁸ The EPA's guidance is to fix your home if radon tests at 4 picocuries per liter or higher, and to consider fixing it between 2 and 4.¹⁹

New Jersey law has the landlord of a one-unit rental, or of a two-unit building the owner doesn't live in, file a certificate of registration with the municipal clerk; landlords of multiple dwellings register with DCA's Bureau of Housing Inspection.²⁰ Every landlord must give each tenant a copy of the certificate of registration, and a copy of any amended certificate within seven days of filing it.²⁰

New Jersey requires single-family, two-family and multiple rental dwellings built before 1978 to be inspected for lead-based paint hazards every three years or at tenant turnover, whichever comes first, unless the unit has a valid lead-safe certificate.⁸ Under P.L.2021, c.182, a covered rental unit's first lead inspection was due by July 22, 2024, or at tenant turnover if that came sooner, and towns must let owners hire a certified lead evaluation contractor directly.⁸ If an inspection finds lead-based paint hazards, the owner must fix them through abatement or lead hazard control, and a lead-safe certificate is good for two years.⁸

EPA's lead renovation rule generally doesn't cover homeowners working on their own pre-1978 homes, but it does apply if you rent out all or part of your home.²¹ Before a renter signs a lease for most pre-1978 housing, federal law requires the landlord to disclose known lead-based paint and hazards, share available records, hand over EPA's Protect Your Family From Lead pamphlet and include a Lead Warning Statement.²²

More than one in four adults 65 and older fall each year.²³ When the new unit is for a parent, a raised ranch's lower level has a head start, since its side door is close to the ground; a single low step or a short ramp and a curbless shower are easiest to include from the beginning. NAHB's Certified Aging-in-Place Specialist (CAPS) credential trains remodelers in home modifications for aging in place.²⁴

When you call the number on this page, a recorded line connects you with one independent company that handles rental conversions in the Central Jersey area. The design, the schedule and the price are agreed between you and that company.

That company pays us for each call, so connecting costs you nothing, and nobody from our side calls or texts you later. How we make money

Look the company up with the state before any money changes hands. New Jersey's Contractors' Business Registration Act requires every home improvement contractor business, from a sole proprietorship up, to register with the Division of Consumer Affairs every year before selling or making home improvements, unless the law exempts it.²⁵ The Division of Consumer Affairs' License Verification System is a real-time lookup; its Business Search finds home improvement contractor businesses by business name, license number or city and lists each one's registration number, license type, status and city.²⁶ Check a New Jersey license

A New Jersey home improvement contract for more than $500, and any change to its terms, must be in writing and signed by all parties, and must list the contractor business's legal name, business address and registration number, include a copy of its liability insurance certificate with the insurer's phone number, and state the total price including any finance charges.²⁷ Write the zoning approval into the contract as a condition, so no work starts before the town has said yes.