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What Are The Dirtiest Areas In The Office?

The dirtiest places in your office building are usually the ones that are overlooked. While most companies try to keep their offices clean, it’s crucial to recognize where these dirty places generally are in order to keep your work environment clean and hygienic.

In an important study by Kimberly-Clark, researchers swabbed thousands of surfaces in office buildings with about 3,000 employees total. The businesses included law firms, insurance agencies, health care providers, and manufacturing enterprises. The study’s swabs were analyzed with an ATP meter, a device commonly used to assess sanitary conditions in industry. It measures levels of adenosine triphosphate (ATP), a molecule found in all animal, vegetable, bacteria, yeast and mold cells.

According to the study carried out by Dr. Charles Gerba, Professor of Microbiology at the University of Arizona, the highest concentrations of adenosine triphosphate found included the following office areas and devices:

  • 21% of vending machine buttons
  • 23% of water fountain buttons
  • 26% of refrigerator door handles
  • 27% of keyboards
  • 48% of microwave door handles
  • 75% of break room sink faucet handles


Let’s take a closer look at some of the dirtiest areas in office environments and how to keep them free of bacteria and hygienic for all work team members.

Faucet Handles In The Break Room

The study above found that 75% of all faucet handles in company break rooms were likely to make people sick by spreading illnesses, and that over 90% should be properly disinfected. Using a hand sanitizer after you touch the handles or a paper towel to turn them on and off would be a safer way to keep yourself and others healthy.

Microwave Handles

The office microwave probably gets more use than you think. Microwave oven interiors host a mix of meat and vegetable particles, which make a perfect breeding ground for bacteria. Germs use warmth, food and water to multiply, and steam from cooked food isn’t hot enough or long enough to kill most bacteria strains.

Computer Keyboard And Mouse

Since your hands are on both of these for hours at a time, they’re full of dead skin cells, food particles, and dust that you can unintentionally bring to any other objects you touch in the office. If you don’t keep them and your hands clean with disinfectant and proper washing, even bacteria that only lives for a few hours on certain surfaces will continue to get reapplied every day of use.

Drinking Fountain Buttons or Handles

A study of water fountains at the Denver public library and a local bus terminal there discovered that they were common sources of rotavirus contamination and influenza A. Before taking a drink, let the water run for about seven seconds, then wash your hands after using the fountain.

Refrigerator Door Handles

Housing leaky food bowls, unwashed take-out containers, and forgotten moldy yogurts, bacteria thrive in unchecked office refrigerators. Make sure somebody cleans out and wipes down the office fridge one a week with a potent antibacterial cleaner. This could be scheduled closer to the beginning of the week or near the end for a fresh start on Monday.


While plenty of people are aware about the risk of germs in the restroom, bacteria like E. coli can cover almost all surfaces there. Even cleaning your hands can be difficult if the faucet handles are especially dirty. You could protect your hand’s contact with the handles by holding a paper towel to turn the water on and off, as well as when you push the handle to flush the toilet.

Office Mugs

Professor Charles Gerba also studied the lives of bacteria on office cups. He discovered that up to 20% of washed office mugs had traces of coliform – the same bacteria in fecal matter. Importantly, once the cups were wiped with a communal washcloth, the number rose up to 100 percent. After being wiped, 20% of mugs also tested positive for E. coli. A good reminder to keep in mind that shared washcloths and sponges should always be avoided when cleaning dishes.

Coffee Maker

Bacteria grow quickly in the moist, dark insides of these machines after use. You can fill a coffee maker with 2 – 3 cups of plain white vinegar, and let that sit for thirty minutes. Then let it run through, following up with three or more cycles of water until the vinegar smell rinses out.

Office Cleaning Methods

To better clean the office, prevent illness and disease, and reduce downtime at work, employers can:

  • Whether your office is cleaned by a professional vendor or an in-house team, ensure that the cleaning program is committed to improving health with cleanliness. Cleaning professionals should use all of the latest equipment, chemical agents, and cleaning methods, including green chemicals and microfiber cleaning cloths, which have been shown to remove germs more effectively than traditional cotton cleaning cloths.
  • Not all businesses will have access or need for a cleaning team with “cleaning for health” expertise, so it’s crucial to implement an effective cleaning routine that everyone in the office can follow. Give special attention to common trouble spots, such as cabinets, flooring tiles, fire extinguishers, light switches, shelving, and windows. Maintain and keep your office vacuum accessible for regular cleaning.
  • Inform employees about staying hygienic and healthy. Companies can reduce the number of illnesses at work by educating employees with the best ways to stay healthy and clean in the office, such as with a best-practices guide or informative signage near frequented areas.
  • Request that sick employees stay home for the benefit of others and their own health. Employees who are sick shouldn’t come to work in order to prevent the spread of illness.


Be certain that your cleaning process or company focuses on the hot spots above, cleaning and disinfecting them every work day. Employers could also create a sign-up schedule for volunteer staff members to start daily spot cleaning and routine disinfecting for the whole office. You might be surprised how some people jump at the opportunity to better protect their environments and fellow employees.