Restroom Contamination Study

From time to time, we are asked about the real cleanliness of restrooms. Even if they look “clean” are they really clean? There is, after all, a health issue beyond appearances.


To explore this issue we implemented a performance measurement system over a 60 day period to examine data comparing facility appearance and health-related goals. An important element of the measurement system utilized bio-waste testing in a cross section of client restrooms. The test measures the amount of an organic compound (creatinine) found in human urine deposited on floors near urinals and toilets.


The sampling was conducted in tenant office facilities, universities and an airport. The sampling schedule was randomized throughout the day to understand how customers might experience the condition of the restroom, whenever they might use it.


Restrooms were first inspected for the attributes that caused the most customer complaints, then bio-waste testing was conducted in several locations within the restroom. The results were tabulated and compared.

Creatinine concentrations were expressed in milligrams (mg) per deciliter (dL). The associated creatinine-connected bacteria count also indicated the aerobic bacteria (bacteria that can grow and live in the presence of oxygen) left on the surface tested.

  • Measurement results of 5 mg per dL or less, indicated low levels of contamination and effective cleaning for health;
  • Levels of 6 mg per dL to 33 mg dL were considered moderate contamination, needing attention and reasonable response;
  • Levels over 34 mg per dL indicated a high level of contamination, which suggested the need for more urgent improvement and continued tracking.

About five (5) percent of the rest rooms tested exhibited creatinine concentration levels of 50 mg per dL or higher.


We closely examined the relationship between appearance and bio-waste contamination. In this study, based on customer-defined attributes, cleanliness appearance ranged between a low of about 74% to a high of about 96% (the higher the percentage, the closer to a defect-free environment as perceived by the customer). Correspondently, creatinine concentration levels ranged from a low of zero (0) mg per dL to a high of 100 mg/dL. Perhaps most interestingly, there was not a high degree of connection between how “clean” a restroom looked and the level of creatinine contamination found.


Indeed, no visually-inspected restroom was judged to be dramatically “dirty” (restrooms were judged to be 74-96 percent “defect-free”). In some cases, where an odor was present, creatinine contamination levels were not materially different from areas where no odor was detected. Our conclusion is that a restroom that looks “clean” may (or may not) have a high level of creatinine concentration. In short, appearances and creatinine measurements can be deceiving!


What could be going on where high contamination levels are found? An effective cleaning program creates both an acceptable appearance of cleanliness, as well as low levels of bio contamination. Medium or higher levels of urine and associated bacteria, can indicate the need to evaluate and improve the restroom cleaning procedures; a key process improvement mandate. Our experience has shown us that process failures might include: poor staff training, ineffective chemicals, inadequate equipment, insufficient chemical dwell time, too long between cleaning frequencies, or just plain lack of control of the cleaning system.

However, an important lesson taken from the study is that the measurement protocol (creatinine concentration) is a very limited tool. While accurate for sampling urine contamination, a creatinine measurement fails to detect a variety of protein-based contamination.


A more comprehensive testing strategy measures adenosine triphosphate (ATP), the universal energy molecule found in all animal, plant, bacterial, yeast and mold cells. The system provides information on the level of contamination for a broader set of contaminants. The drawback with ATP testing is the cost of reliable equipment, which can range from $1,000 to $4,000 per unit. Nonetheless, this testing model can be used beyond restrooms and can provide relatively accurate contamination readings in kitchens, dining areas, elevators and even offices in an environment where monitoring cleaning for health is a priority. Given these advantages, I suggest that future studies use an ATP strategy.


Adapted and reprinted by permission of Cleaning and Maintenance Management magazine.

Vince Elliott is the President and CEO of Elliott Affiliates, Ltd. of Baltimore, MD. He is widely recognized as a leading authority in the design and utilization of performance-based management techniques and continuous improvement systems for cleaning and facilities outsourcing. Vince is a member of the Association for Quality and Participation (AQP); the American Society for Quality (ASQ), where he is a past chairman of the Facilities Management Quality Control Committee; and a member of the Cleaning Management Institute (CMI). He is also a member of the International Facilities Management Association (IFMA), the Building Owners & Managers Association (BOMA), CoreNet Global, International Sanitary Supply Association (ISSA), and (NCMA) National Contract Management Association.