Biofilms Linked to Millions of Illnesses, Billions in Healthcare Costs
By Robert B. Bender
While most Americans assume their drinking water is safe once it leaves a treatment plant, researchers are warning of a hidden threat lurking inside the nation’s plumbing systems: biofilms.
According to research cited by the U.S. Centers for Disease Control and Prevention (CDC), biofilms contribute to more than 7 million waterborne illnesses, 600,000 emergency room visits, 118,000 hospitalizations, and over 6,000 deaths annually, costing the U.S. healthcare system more than $3.3 billion each year.
Biofilms are slimy communities of bacteria, fungi, amoebas, and other microorganisms that attach themselves to surfaces inside water pipes, cooling towers, hot water systems, decorative fountains, and industrial equipment. Once established, these microbial colonies create a protective matrix that shields them from disinfectants, antibiotics, and even aggressive chemical treatments.
The ‘New Frontier’ of Waterborne Disease
CDC researchers describe biofilms as a major public health challenge. Unlike traditional concerns over contaminated drinking water, many modern outbreaks originate from microorganisms growing within building plumbing systems.
“Biofilms provide a safe haven for microbes, protecting them from disinfectants,” according to CDC researchers. This protection allows dangerous pathogens such as Legionella bacteria — the cause of Legionnaires’ Disease — to survive and multiply before being released into the air through showers, cooling towers, and fountains.
The CDC found that more than 90% of deaths associated with waterborne diseases are caused by just a handful of biofilm-associated pathogens. Legionella alone is responsible for nearly 1,000 deaths annually in the United States.
Why Biofilms Are So Difficult to Eliminate
Research published in Scientific American explains that biofilms are far more sophisticated than simple bacterial growth.
Scientists have discovered that bacteria within biofilms communicate through chemical signaling systems, coordinating growth and defense mechanisms. The biofilm’s protective matrix acts like a fortress, preventing disinfectants and antibiotics from penetrating deeply enough to kill the organisms within.
Studies have shown that even chlorine bleach can struggle to eradicate established biofilms. While surface bacteria may be destroyed, microorganisms buried deeper within the biofilm often survive and quickly repopulate the colony.
Researchers also note that biofilms are responsible for significant industrial problems, including accelerated corrosion, reduced heat transfer efficiency, equipment fouling, and increased maintenance costs in cooling towers, boilers, and heat exchangers.
Aging Infrastructure Adds to the Challenge
Experts point to aging water infrastructure as a growing concern. The United States relies on approximately six million miles of plumbing to deliver drinking water, sanitation, cooling, and heating services. As pipes age, conditions become increasingly favorable for biofilm development.
The CDC emphasizes that, while water is heavily regulated up to the water meter, maintaining water quality within buildings often falls to property owners and facility managers.
Emerging Technologies Seek Solutions
As awareness of biofilm-related risks grows, researchers and industry innovators are pursuing new approaches beyond traditional chemical treatment.
Scientists studying biofilms have focused on disrupting the communication systems bacteria use to organize colonies. By interfering with these signaling pathways, researchers hope to prevent biofilm formation before it becomes established.
At the same time, private-sector companies are introducing technologies designed to reduce scale, corrosion, and biofilm accumulation within water systems without relying on chemicals. These approaches seek to address the root conditions that allow biofilms to thrive while reducing maintenance requirements and environmental impacts.
A Growing Focus for Facility Managers
For facility managers, healthcare institutions, schools, commercial buildings, and industrial facilities, biofilms are increasingly recognized as a critical water management issue.
The CDC recommends regular flushing of infrequently used plumbing systems, maintaining proper hot water temperatures, and implementing comprehensive water management plans to reduce microbial growth.
As scientific understanding continues to evolve, one message is becoming clear: the battle for safe water no longer ends at the treatment plant. It continues inside the pipes, where microscopic biofilm communities can have enormous consequences for public health, infrastructure reliability, and operating costs.
“The new frontier,” researchers say, is learning how to prevent these hidden microbial cities from taking hold in the first place.
Robert B. Bender is the executive vice president of North America Water Technology, Inc.