NJ Carbon Monoxide Detector Rules: A Plain Guide

Which homes the rule covers

The Division of Fire Safety's bulletin on carbon monoxide detection explains the rule under the state Uniform Fire Code. For one- and two-family dwellings, CO alarms are required when the building contains a fuel-fired appliance or has an attached garage. In an older New Jersey house, that is nearly always the case: a gas or oil boiler in the basement, a gas water heater, a gas range, a wood or gas fireplace, or a pellet or wood stove all count as fuel-fired.

The same bulletin notes that, effective September 3, 2017, the requirement to have CO detection in buildings with fuel-fired equipment or an attached garage was extended to all buildings, not only homes. Apartment buildings, hotels and similar occupancies have their own, more detailed options for where alarms must go. It also says buildings that met the earlier construction-code CO rules at the time they were built are not required to meet the newer fire-code provisions.

Where the alarms go

For one- and two-family homes, the bulletin places CO alarms in the vicinity of the bedrooms, and says they may be battery-operated, plug-in or hard-wired. A state guidance sheet for construction officials adds that CO alarms may be placed anywhere on the ceiling or the wall, and that installing battery or plug-in CO alarms does not require a permit or an inspection.

Within those rules, follow the alarm maker's instructions for mounting height and distance from appliances, kitchens and bathrooms. A sensible extra, beyond what the rule requires, is an alarm on the level with the boiler or furnace, so a leak at the source is picked up before it spreads upstairs.

Common situations at a glance

Here is how the state documents apply in typical one- and two-family homes. Your town's fire official has the final word.

• Gas or oil boiler, furnace or water heater: required near the bedrooms; fuel-fired appliance
• Wood fireplace or stove, no gas service: required near the bedrooms; solid fuel counts as fuel-fired
• All-electric home with an attached garage: required near the bedrooms; the garage triggers it
• All-electric home, no attached garage: not triggered by the state rule; many owners install one anyway
• Home being sold or newly rented: checked for the municipal certificate; smoke alarms and extinguisher too

Selling or renting: the certificate

State fire code rules require that before a one- or two-family or attached single-family home is sold, leased or otherwise changes occupancy, the owner obtain a certificate of smoke alarm, carbon monoxide alarm and portable fire extinguisher compliance from the enforcing agency. A state press release explains that the certificate is obtained through the municipality where the home is located and is valid for six months from the date of issue. Some towns that already run their own resale or rental inspection under a local code handle it through that process instead.

A January 2026 state advisory bulletin says that under a 2025 law, inspections under the Uniform Fire Safety Act must be done by licensed fire inspectors, including the alarm certificate inspections towns perform at a sale or change of tenant. The bulletin refers to the certificate under an updated name that also covers secondary power source identification labels. Ask your town's fire official what applies when you list the house.

What the certificate inspection checks

The certificate inspection is about alarms and the extinguisher, not the chimney. Based on the state rule and press materials, expect these items. Details and scheduling are set by your town.

• Smoke alarms on each level, including the basement, and within ten feet outside each separate sleeping area
• Ten-year sealed battery smoke alarms where battery units are used, with hard-wired alarms kept where they were originally installed
• CO alarms near the bedrooms when the home has fuel-fired equipment or an attached garage
• A listed portable fire extinguisher within ten feet of the kitchen, in the path of exit, mounted on its bracket and easy to see
• The extinguisher's instructions left for the new occupant

Renovations and permits

When you pull a construction permit for repair, renovation or alteration work, state guidance tells construction officials to notify the applicant that smoke and CO alarms need to be installed where they were not part of the original construction. The same guidance says installing the alarms is not a prerequisite to getting the permit, and that the construction code does not make the contractor responsible for installing them. In plain terms, the alarms are the owner's job, and the permit office reminds you rather than holding up the work.

The renovation most closely tied to carbon monoxide is replacing a boiler, furnace or water heater that vents into an existing chimney. For that work, the state's chimney verification form asks the person verifying the chimney to confirm it is in good repair, clear of obstruction and properly lined and sized for the new appliance. That paperwork goes with the permit, so the chimney gets a look at the moment the venting changes, which is also the moment CO problems are most likely to start.

The chimney behind the alarm

A CO alarm tells you exhaust is getting into the living space. It does not tell you why. In older New Jersey homes, the boiler and water heater often vent into a masonry chimney, and the usual culprits are a flue blocked by fallen tile, soot or a nest, a clay liner that has cracked or separated, a rusted or loose connector pipe, or a flue that is too large for a modern gas appliance and does not draft well. A furnace or boiler replacement can change how the chimney behaves, which is one reason the state asks for chimney verification with the permit.

If an alarm sounds, or anyone has symptoms, get everyone outdoors first, then call 911 or the gas company once you are out. Do not go back in to look for the source. Once the home is cleared, the appliance and its flue should be checked before they are used again.

Check locally before relying on this

This is a plain summary of state documents, not legal advice. Rules are updated, towns run their own inspection programs, and your municipal fire official or construction office has the final word for your address. For the chimney side, NFPA 211 calls for chimneys and vents to get a yearly inspection, which is the habit that keeps the alarm quiet in the first place.