About 32% of janitors work in the services to buildings and dwellings, and another 14% are employed in elementary and secondary schools. The remainder are employed throughout other industries.

Most janitors and building cleaners work indoors, but some work outdoors part of the time, sweeping walkways, mowing lawns, or shoveling snow. They spend most of the day standing, sometimes moving or lifting heavy supplies or equipment. As a result, the work may be strenuous on the back, arms, and legs. And some tasks, such as cleaning bathrooms and trash rooms, can be dirty and unpleasant.

Janitors and building cleaners have one of the highest work-related injury rates. Workers may suffer cuts, bruises, and burns from machines, tools, and chemicals.

Most janitors and building cleaners work full time, but a significant number work part time. Because office buildings are usually cleaned while they are empty, many cleaning workers work evening hours. Janitors in schools, however, usually work during the day. When there is a need for 24-hour maintenance, janitors may work in shifts. This is particularly true of hospitals and hotels.