NYC Carbon Monoxide Detector Rules: A Plain Guide

What the city requires of building owners

The city's housing agency, HPD, spells out the owner's side in its guide for building owners and on its fire safety page. The duties are specific, and they apply to every apartment in the building, not just the ones near the boiler room.

HPD frames detectors as an early warning rather than a cure, and that is the right way to think about them. The rules decide who installs and maintains the alarm; they say nothing about whether the boiler flue above it is sound, which is a separate question covered further down.

• Install at least one approved and operational carbon monoxide detector in each dwelling unit
• Place it within 15 feet of the primary entrance to each sleeping room
• Use a detector with an audible end-of-useful-life alarm
• Give tenants written information on how to test and maintain it
• Provide an approved, working smoke detector in each apartment as well

What tenants are responsible for

HPD says tenants are responsible for maintaining the detectors, including testing them and replacing batteries. If a detector was lost or not properly maintained and the owner has to replace it, the owner may charge a fee set by law.

If your apartment does not have working smoke and CO detectors, HPD's advice is to tell the property owner first, and if it is not corrected, register a complaint by calling 311. Keep a note of when you reported it and to whom, since that record helps if the complaint goes further.

• Install an approved CO detector in each unit: the owner
• Place it within 15 feet of each bedroom entrance: the owner
• Give written testing and care instructions: the owner
• Test the detector and replace batteries: the tenant
• Report a missing or broken detector: the tenant tells the owner, then calls 311; the owner fixes it

One- and two-family homes, co-ops and condos

New York State Executive Law section 378 says every one- or two-family dwelling, every dwelling unit in a building owned as a condominium or cooperative, and every multiple dwelling in the state must have an operable carbon monoxide detector. The requirement applies where the home has appliances, devices or systems that may give off carbon monoxide, or an attached garage.

In practice that covers a great many homes in the five boroughs, since a gas or oil boiler, a water heater, a gas range, a gas dryer or a fireplace all burn fuel. Co-op and condo buildings may divide these duties between the board and the unit owners, so check with your board or managing agent about who supplies and who replaces the detector.

What to do when the alarm sounds

HPD's fire safety guidance is direct: if a carbon monoxide alarm sounds, get out immediately and call 911. Do not stay to find the source, and do not silence the alarm and go back to bed. If anyone feels unwell, tell the dispatcher. Gas utilities also respond to suspected leaks and carbon monoxide calls.

Once the fire department or utility has cleared the home, the appliance and its venting still need to be looked at before they run again. A detector that went off once for a reason is likely to go off again if nothing changes.

Where to put the detector in practice

Start with the rule: within 15 feet of the entrance to each bedroom. Then follow the detector's instructions for height and mounting, since carbon monoxide mixes with room air and each model lists its own spot. Adding an alarm in the basement or on the floor with the boiler gives warning closer to the source, which matters in a brownstone or two-family house where the boiler is two floors below the bedrooms.

Keep detectors out of bathrooms and away from vents, fans and the boiler itself, where steam or a brief burst of exhaust at start-up can cause false alarms. Note the replacement date printed on the back; the end-of-life chirp is a reminder, not a fault.

Choosing and testing a detector

Detectors come battery-powered, plug-in or hardwired, and some combine smoke and carbon monoxide sensing in one unit. Any of them can meet the rule if it is approved and placed correctly. Combination units save ceiling space, but a separate CO alarm near the boiler can still be worth having in a house with fuel-burning equipment in the basement.

Testing is quick: press the test button and listen for the full alarm pattern. Do it monthly, after any power outage for plug-in and hardwired units, and whenever you return from a long trip. Replace the whole detector when it reaches the end-of-life date or starts its end-of-life signal, rather than just changing the battery.

Common sources in older city buildings

In the buildings we work on, carbon monoxide trouble rarely starts with a single dramatic failure. It usually builds: a boiler flue that is partly blocked by fallen tile or scale at its base, a water heater left alone in a flue sized for an old oil boiler so its exhaust cools and lingers, a smoke pipe that has rusted through at the joint, or a chimney top blocked by a nest or debris.

The kitchen is the other common source. HPD warns never to use the oven or gas range to heat the home, because doing so can produce dangerous levels of carbon monoxide. In a cold snap, that warning is worth repeating to everyone in the household.

Why the chimney is part of the picture

Most older NYC homes vent a boiler or water heater into a masonry chimney. When that flue is blocked, cracked or badly oversized, exhaust can come back into the house, and the detector is what tells you. It does not fix the cause. NFPA 211 calls for chimneys and vents to be inspected every year, and that inspection is how blocked flues, failing liners and rusted connectors get found before an alarm does the finding.

For a landlord, pairing the detector rules with that yearly inspection makes sense: the detectors protect each apartment, and the inspection keeps the shared boiler flue from becoming the reason they sound. For a homeowner, the same logic holds on a smaller scale, with the added step of having the flue checked whenever the boiler or water heater is replaced, since a new appliance can change what the chimney needs.

Check the current rules before relying on this

This is a plain summary, not legal advice. City and state rules change, and different requirements can apply to new construction, renovations and buildings of different types. For your building, check HPD's current pages, call 311, or ask the Department of Buildings or a licensed professional.