All states have laws (statutes) that require landlords to install and maintain smoke detectors in leased residential premises (apartments, homes).

Some states such as Iowa, Maine, Massachusetts, Ohio, and Vermont require photoelectric or ionization sensors—at least in new construction. And Oregon requires smoke detectors with a HUSH mechanism that allows the alarm to be silenced or temporarily desensitized for 7 minutes while a known condition such as cooking is causing the alarm to activate.

Most states also require landlords to install and maintain carbon monoxide detectors in leased residential premises. Smoke and carbon monoxide detectors are widely available in the same device.

In Maryland, state law requires landlords to install and maintain smoke detectors in leased residential properties. Maryland's Public Safety Article, Section 9-104 mandates that smoke detectors be present in all residential buildings, including rental properties. These devices must be installed in accordance with the State Fire Prevention Code. Maryland law also requires the installation and maintenance of carbon monoxide detectors in residential rental properties. Specifically, the Maryland Annotated Code, Public Safety Section 12-1103, stipulates that carbon monoxide alarms must be installed in certain residential properties, including those that contain a fuel-burning appliance, have an attached garage, or are enclosed parking. Landlords are responsible for installing the required detectors and ensuring they are in good working order at the beginning of a tenancy, while tenants are typically responsible for the upkeep of the detectors during their tenancy, such as replacing batteries. It is important for landlords to comply with these regulations to ensure the safety of their tenants and to avoid legal penalties.