Local Law 157: NYC natural gas alarm requirements

What is Local Law 157?

Local Law 157 of 2016 requires natural gas alarms, also called gas detectors or methane detectors, in New York City homes with gas service. A natural gas alarm sounds when leaking gas builds up in the air, before it reaches an explosive level.

Local Law 102 of 2025 set the current deadline: alarms must be installed on or before January 1, 2027. The Department of Buildings (DOB) confirmed that date on October 13, 2026, and HPD inspectors will start checking for gas alarms in 2027.

Which buildings need gas detectors?

The building owner must buy and install the alarms in:

• Class A multiple dwellings: apartment buildings with three or more units, including rentals, co-ops and condos.
• Class B multiple dwellings: transient housing such as rooming houses and some hotels. These can use an alarm in each unit, or a line-operated, zoned gas detection system in all public corridors and spaces.
• One- and two-family homes that are not owner-occupied.

Buildings with no gas piping or gas service are exempt.

Which apartments and rooms need an alarm?

• Every apartment with a gas appliance, such as a gas stove, oven, dryer or water heater. The alarm goes in the same room as the appliance.
• Common spaces with a gas appliance, such as a laundry room with gas dryers.
• Apartments directly above gas. DOB’s FAQ says an apartment with no gas appliance can still need an alarm when a gas appliance or gas piping is directly below it. It goes on the ceiling, or within 12 inches of it, in the room above.

DOB’s FAQ lists these as not needing an alarm:

• Centralized, restricted rooms that house boilers, water heaters or generators.
• Apartments and common areas with gas piping but no gas appliance, unless there is gas directly below.
• Commercial restaurant kitchens in mixed-use buildings.

Where to install a natural gas alarm

The DOB rule (1 RCNY §908-02, which adopts NFPA 715-2023) sets the placement:

• Put the alarm in the same room as the gas appliance.
• Keep it at least 3 feet and no more than 10 feet from the appliance, measured horizontally.
• Mount it on the ceiling, or on a wall within 12 inches of the ceiling. Natural gas is lighter than air and rises.
• If the room is too small for the 3-foot distance, follow the manufacturer’s instructions and NFPA 715.

Extra alarms outside sleeping areas are only needed where NFPA 715 requires the alarms to be interconnected.

Which gas detectors are approved?

The alarm must be listed and labeled to UL 1484, the standard for residential gas detectors, and built to NFPA 715-2023. DOB does not endorse brands, but its October 13, 2026 announcement named these battery-operated, UL 1484-listed models as a partial list:

Other compliant models may exist, so always check for the UL 1484 label. A carbon monoxide (CO) alarm on its own does not count, because it does not detect natural gas. Combination natural gas and CO alarms are available. If you are also replacing smoke or CO alarms, see our NYC smoke and carbon monoxide detector rules.

Battery, plug-in or hardwired?

• Existing buildings (Certificate of Occupancy or TCO issued before January 1, 2027) may use battery-powered alarms.
• Newer buildings (CO or TCO issued after January 1, 2027) need AC power with a backup power source.
• Battery and plug-in alarms can be installed by the owner, the super, maintenance staff or the tenant. No licensed electrician is needed.
• Hardwired alarms must be installed by a New York City licensed electrical contractor, who gets the permits.

Who pays? Tenant reimbursement

The owner buys, installs and replaces the alarms. In Class A buildings, the owner may collect a reimbursement from the tenant, who has one year from installation to pay:

Tenants in Class B buildings don’t reimburse. In non-owner-occupied one- and two-family homes, the reimbursement is $25 per gas alarm. The same amounts can apply to replacements needed because of tenant neglect, loss or damage.

Notices and records owners must keep

• Post a notice in the building entrance or a common area. HPD publishes sample language, and a digital display is allowed.
• Give a notice to an adult in each apartment when the alarm is installed, covering testing, maintenance and what to do if it sounds.
• Keep records of the date the notice was posted, the installation date for each apartment or location, and each alarm’s end-of-life date from the manufacturer.

Records must be available if HPD, DOB, FDNY or the Health Department asks for them. Our one-page Local Law 157 checklist (PDF) covers every step, including the notices and records.

Inspections and violations

HPD code inspectors will check for natural gas alarms starting in 2027. An alarm that is missing, broken or in the wrong place can lead to a violation and fines. Owners must also replace each alarm when it reaches the end of its useful life.

What tenants must do

• Test the alarm at least once a month.
• Replace replaceable batteries with the recommended type, and right away when the low-battery warning sounds.
• Never paint over, cover or remove the alarm.
• Replace an alarm that goes missing or stops working during their tenancy.

Frequently asked questions

Is the NYC gas detector deadline still January 1, 2027?

Yes. Local Law 102 of 2025 allowed DOB to push the date to 2029 if fewer than four manufacturers made compliant battery-powered alarms. DOB's October 13, 2026 announcement named models from five manufacturers and kept the January 1, 2027 deadline.

Do I need a gas detector if my apartment has a gas stove?

Yes, if the building is covered by Local Law 157. The owner must install a natural gas alarm in the room with the stove, 3 to 10 feet from it and on or near the ceiling.

Does a carbon monoxide detector count as a gas detector?

No. A CO alarm detects carbon monoxide, not natural gas. You need an alarm listed to UL 1484, or a combination natural gas and CO alarm.

Can a landlord install gas detectors without an electrician?

Yes, for battery-powered and plug-in alarms. Only hardwired alarms need a New York City licensed electrical contractor.

Do co-ops and condos need gas detectors?

Yes. Co-op and condo buildings are Class A multiple dwellings, so they are covered by Local Law 157.

How many gas detectors does my building need?

At least one in each apartment with a gas appliance, plus common spaces with gas appliances and apartments directly above gas. Send us your unit count and we can help you work out the number.

Where can I buy gas detectors for NYC buildings?

AlarmsNY supplies UL 1484 natural gas alarms by the case to landlords, property managers and contractors, delivered to all five boroughs. Call or WhatsApp (929) 421-9452, or email sales@alarmsny.com.

Sources

• HPD: Smoke, Carbon Monoxide, and Natural Gas Detectors
• DOB: Natural Gas Detection Devices FAQs
• DOB announcement, October 13, 2026
• 1 RCNY §908-02, DOB natural gas alarm rule (PDF)
• Local Law 102 of 2025 (PDF)

General information for building owners, not legal advice. Rules can change, so confirm the details for your building with HPD or DOB.