NYC Smoke, CO, and Gas Detector Laws: What Owners and Tenants Must Know

Almost every New Yorker knows there is supposed to be a smoke alarm in the apartment, and most know there is supposed to be a carbon monoxide alarm too. Far fewer know that the list is about to become three devices long, or that the law is very specific about which half of the job belongs to the landlord and which half belongs to the person living there.

That split is where most disputes start. A tenant assumes a dead alarm is the owner’s problem; an owner assumes the tenant should have changed the battery. New York City actually answers this question in detail — including the exact dollar amount an owner may charge a tenant for a new device. Here is what the law requires, who is on the hook for each piece of it, and the deadline that is coming for every gas-heated building in the five boroughs.

Three devices now, not two

Smoke alarms have been required in New York City dwellings for decades. Carbon monoxide alarms joined them under Local Law 7 of 2004. The third device is new: Local Law 157 of 2016 requires natural gas detectors in dwelling units, and after one deferral the compliance date now lands on January 1, 2027.

That third device is the one worth acting on early, because it is the only one most buildings do not already have anywhere. If your building burns gas — a range, a boiler, a water heater, a dryer — you are in scope. Buildings with no gas service at all are exempt.

Smoke alarms: what the code actually says

The owner must provide and install at least one approved and operational smoke alarm in every dwelling unit, positioned within 15 feet of each room used for sleeping. In a typical apartment layout, a single alarm in the hallway outside the bedrooms satisfies that. In a railroad apartment or a brownstone floor-through, it often does not, and you need more than one.

Since April 1, 2019, New York State has required that any smoke alarm sold in the state be either hardwired or powered by a sealed, non-removable battery with a ten-year life. The point of that rule is to remove the failure mode that killed people for thirty years: a battery pulled out to stop the chirping and never put back. The law did not force anyone to rip out an existing compliant alarm on day one, but any replacement you buy today will be a sealed ten-year unit.

Smoke alarms also expire. There is a manufacture or replacement date printed on the back of the unit, and the sensor degrades whether or not the alarm has ever gone off. An alarm that chirps, that has yellowed, or that is past its printed date is not a working alarm in any sense that matters.

Carbon monoxide alarms

The CO requirement is written to a slightly different measurement: an approved carbon monoxide alarm must be installed within 15 feet of the primary entrance to each room used for sleeping. It applies to dwellings with a fuel-burning appliance or an attached garage, which in New York City means very nearly everything.

In practice, most owners install a combination smoke/CO unit and satisfy both rules with one device in one spot. That is legitimate and it is what we install most often. Just know that CO sensors have a shorter service life than smoke sensors — commonly five to ten years depending on the model — so a combination unit is governed by whichever date is printed on it, not by the smoke alarm’s ten years.

Natural gas detectors and the January 1, 2027 deadline

Local Law 157 of 2016 sat dormant for years waiting on a technical standard. That standard arrived, the Department of Buildings issued its rule, and the compliance date was pushed from 2025 to January 1, 2027. The requirement reaches private dwellings and Class A and Class B multiple dwellings — rentals, co-ops, condos, one- and two-family houses — wherever there is gas service.

The placement rule is unusual, and it is the part people get wrong. A natural gas detector goes between 3 and 10 feet horizontally from each gas-burning appliance, measured within the same room, and it must sit on the ceiling or on a wall no more than 12 inches below the ceiling. Natural gas is lighter than air, so a detector mounted at outlet height — where people instinctively put things — is in the wrong place. Too close to the range is also wrong, because normal cooking will nuisance-trip it.

Owners also carry a notice obligation under the gas-detector rule: occupants have to be told what the device is, how to test and maintain it, what its useful life is, and what to do if it sounds. That last point matters more than it sounds. If a gas detector alarms, you leave and you call Con Edison from outside — not from the apartment, because operating anything electrical in a gas atmosphere is itself an ignition source.

Who is responsible for what — and who pays

This is the part worth reading twice, whether you own the building or rent in it. New York City does not put the whole burden on either side. It splits it.

The reimbursement rule almost everyone gets wrong

An owner may require a tenant to reimburse the cost of providing and installing a device, but the amounts are capped: up to $25 per device, or up to $50 where a combined smoke and carbon monoxide unit is installed. The tenant has one year from the installation date to pay it. That is the whole of it — it is a one-time contribution toward the hardware, not a service charge, not rent, and not a bill an owner can reissue every time a battery dies.

The other half of the same rule cuts the other way. If a device stops working within one year of installation because of a manufacturing defect, through no fault of the occupant, the owner has to replace it — within 30 days of receiving written notice. Written is the operative word. A comment to the super in the lobby does not start that clock; an email or a letter does. Tenants who later find themselves in a dispute almost always wish they had sent the email.

Co-ops and condos: who counts as the owner?

In a rental, “owner” is simple. In a co-op or condo it is the question that stalls the work. For Housing Maintenance Code purposes the building — the co-op corporation or the condo board acting through managing agent — generally carries the owner-side duties for the building, while a shareholder or unit owner who sublets is stepping into the owner role toward their own tenant.

The practical consequence is that alarm compliance in these buildings is usually handled building-wide rather than unit by unit, and the gas-detector rollout for 2027 is very much that kind of project. If you are a shareholder wondering whether you can just buy three detectors and put them up yourself, read our guide to what electrical work needs board approval in a NYC co-op or condo first. Battery and plug-in devices are usually yours to install. Anything hardwired is not.

What non-compliance actually costs

A missing or inoperable smoke or CO alarm is not a paperwork problem. HPD classifies it as immediately hazardous — a Class C violation, the most serious class, with a correction window measured in hours rather than months. It carries civil penalties, it has to be certified as corrected, and it sits on the building’s record where a buyer’s attorney, an appraiser, or a lender will find it.

There is an insurance dimension too. After a fire, the first question anyone asks is whether there was a working alarm. An owner who cannot show that there was is in a materially worse position on both the claim and any resulting litigation. If you are already dealing with a notice from the city on other electrical work, the same discipline applies — see our guide to removing an ECB electrical violation in NYC.

When this is a job for a licensed electrician

Plenty of this you can do yourself. A sealed ten-year battery smoke/CO unit is a screwdriver and ten minutes. A plug-in or battery gas detector is less than that. Nobody needs to call an electrician to put up a battery alarm in the right place, and we would rather you put one up tonight than wait for an appointment.

Where it becomes our work is anything hardwired. New construction and gut renovations are held to a higher standard than a battery unit satisfies: alarms that are hardwired and interconnected, so that one alarm sounding sets off every alarm in the unit. That is the configuration that gets people out of a back bedroom when the fire starts in the kitchen, and it cannot be retrofitted casually — it needs a circuit, boxes, and interconnect wiring pulled between devices.

• Your walls are already open. If you are mid-renovation or mid-rewire, this is the cheapest hardwired interconnected alarm system you will ever install. Adding it later means opening ceilings again. Our house rewiring service includes it as a matter of course.
• An existing hardwired alarm is chirping or dead. Hardwired units are wired into a branch circuit, and replacing one means matching the interconnect and confirming the circuit is healthy — not just clipping in a new device.
• You are adding detectors to a pre-war apartment. Old buildings have their own complications, covered in our guide to pre-war apartment electrical problems in NYC.
• The gas detector needs to be hardwired. Building-wide rollouts often go hardwired for maintenance reasons, and that means new circuits and, generally, a DOB electrical permit.
• You want it documented. If you are an owner, permitted and inspected work is what you show later. See electrical safety inspection.

A five-minute check you can do tonight

1. Count them. Is there an alarm within 15 feet of every room anyone sleeps in? Count the room the kid sleeps in, and the living room if someone sleeps on the couch.
2. Press the test button. On every device. A chirp is not a pass; the test button is.
3. Read the date on the back. Take the unit down and look. Past the printed date means replace, no matter how it sounds when you test it.
4. Confirm you have CO coverage. If your only device says “smoke” and nothing else, you are missing half of what the law requires.
5. Look at your gas appliances. Range, boiler, water heater, dryer. Each of those rooms will need a gas detector before January 1, 2027.
6. If you rent and something is wrong, email your landlord or managing agent. In writing, with the date. That single email is what puts the 30-day clock on the right party.

None of this is expensive relative to what it prevents, and the hardware side of it is genuinely cheap. What costs money is doing it late, in a finished ceiling, under a violation. If you want the work done properly — combination units placed to code, hardwired and interconnected alarms, or a building-wide gas-detector plan ahead of the 2027 date — that is our smoke and CO detector installation service, and we handle it for single apartments and whole buildings alike.

AE Electric is a licensed and insured electrical contractor working across all five boroughs. If you need an alarm survey, a hardwired installation, or a straight answer about what your building has to do before 2027, call (646) 846-0008 or see our residential electrician services.

This article explains New York City requirements in general terms and is not legal advice. Requirements change, and HPD and the Department of Buildings are the authoritative sources for your specific building and occupancy class.