Carbon monoxide is an odorless, tasteless, invisible gas. Carbon monoxide poisoning is a serious public health concern. Learn more about carbon monoxide poisoning.

In Maryland, carbon monoxide alarms must be installed in certain dwellings. This includes hotels, lodging or rooming houses, and rental dwelling units. This requirement also applies to a dwelling that relies on a fossil fuels (e.g., wood, kerosene, gasoline, charcoal, propane, natural gas, and oil) for heat, ventilation, hot water, or clothes dryer operation and is a newly-constructed dwelling with a building permit issued on or after January 1, 2008.

Read the Law: Md. Code, Public Safety, § 12-1102

Topics on this page:

• What is a carbon monoxide alarm?
• Where do I have to install the alarm?
• Can I buy a combination smoke and carbon monoxide alarm?
• Can I paint over the alarm or otherwise mess with it?
• Do other laws apply to me?

What is a carbon monoxide alarm?

In Maryland, a carbon monoxide alarm is a device that is capable of detecting carbon monoxide. When sensing an unhealthy accumulation of carbon monoxide, the device is capable of emitting a distinct and audible sound that warns the occupants. The device must carry the listing of a nationally recognized testing laboratory approved by the Office of the State Fire Marshal and be hard wired into an alternating current (AC) power line with secondary battery backup.

For hotels, lodging or rooming houses, or a rental dwelling unit, the carbon monoxide alarm is:

• wired into an alternating current (AC) powerline with second backup;
• battery-powered, sealed, tamper resistant, and using a long-life battery that has a life of 10 years or more; or
• connected to an on-site control unit that monitors the carbon monoxide alarm remotely so that a responsible party is alerted when the device activates the alarm signal and receives its primary power from a battery or the control unit.

Read the Law: Md. Code, Public Safety, § 12-1101

Where do I have to install the alarm?

A carbon monoxide alarm must be installed in a central location outside of each sleeping area OR, if there is a centralized alarm system capable of emitting a distinct and audible sound to warn all occupants, the carbon monoxide alarm may be installed within 25 feet of any carbon monoxide-producing fixture and equipment.

There are more specific installation requirements for hotels, lodging or rooming houses, and rental dwelling units. For example, in a rental dwelling unit, a carbon monoxide alarm must be installed outside and in the immediate vicinity of each separate sleeping area and on every level of the unit, including the basement.

Read the Law: Md. Public Safety, § 12-1104

Can I buy a combination smoke and carbon monoxide alarm?

Yes, a carbon monoxide alarm may be combined with the smoke alarm if it meets the requirements of the law.

Read the Law: Md. Code, Public Safety, § 12-1103

Can I paint over the alarm or otherwise mess with it?

No. Except as part of routine maintenance, you may not render a carbon monoxide alarm inoperable.

Read the Law: Md. Code, Public Safety, § 12-1105

Do other laws apply to me?

Your local county or municipal corporation may enact more stringent laws that relate to carbon monoxide alarms. Check with your specific county to see if additional requirements affect you.

Read the Law: Md. Code, Public Safety, § 12-1106