Waterborne Disease in the United States

Background

In a CDC analysis, researchers defined waterborne disease as a disease caused by a pathogen (bacteria, virus, or parasite) spread through water. The diseases were based on surveillance data, administrative data (for example, hospital records), or literature reports using the following criteria:

• Likely to cause substantial illness or death
• Caused by waterborne pathogens in the U.S.
• Availability of data to accurately determine related health outcomes

These estimates did not include exposures from toxins, such as harmful algal blooms, and chemicals such as lead.

Changes in waterborne disease

Waterborne diseases affect over 7 million people in the U.S. every year and cost our healthcare system over $3 billion.

CDC's 2000-2015 estimates of the impact of waterborne disease in the U.S. highlight a shift in the types of diseases and routes of exposure that are most common over the last several decades. In the first part of the 20th century, germs in drinking water caused most waterborne diseases. These diseases, like cholera and typhoid, caused serious gastrointestinal illness and sometimes resulted in death. Once effective and consistent drinking water treatment, disinfection, and sanitation measures were put into place across the country, these diseases became rare.

Today, we are realizing that waterborne diseases are responsible for many different types of illnesses—including respiratory illnesses, neurological illnesses, skin problems, gastrointestinal illnesses, and bloodstream infections. People are infected by waterborne germs not just when they drink water, but also when they breathe in contaminated water droplets or when water gets in their ears or nose.

Reasons for this change

To understand what caused the change in the types of diseases we are facing and how people are becoming sick, we must look at how our water use has evolved. As the population grew, so did the need to use water on a larger scale and in new ways. To meet these demands, structures like high rises, hospitals, and water parks were built. These new buildings required complicated water systems that went through thousands of gallons of water every day. However, the complex water systems used by these structures were added to existing piping systems, many of which were designed in the early 1900s.

Water travels further in these complex water systems because of the large number of pipes, drains, and other plumbing fixtures. This makes it harder to maintain water quality and to keep enough disinfectant in the system to kill germs. As a result, these pipes can become a home for water-related germs that grow in pipe slime (also known as biofilm). While biofilm germs cause only a small percentage of waterborne diseases, the illnesses resulting from these diseases are responsible for the majority of waterborne disease-related hospitalizations and deaths.

Preventing waterborne illnesses

To control these germs and help prevent future waterborne illnesses, we need a wide-ranging approach that brings together policy makers, industry partners, building managers, public health, and other stakeholders, and includes:

• Maintenance of and updates to our water system infrastructure
• Increased support for waterborne disease-focused public health work to support state, local, and territorial health departments in:
  • Tracking, investigating, reporting, and preventing disease
  • Understanding emerging issues and threats
• Updated estimates and development of additional burden estimates looking at disease attribution by water type
• Encouragement of owners/managers of large buildings—such as healthcare facilities, hotels, and recreational water facilities—to follow existing policies/regulations and best practices (for example, the Model Aquatic Health Code [MAHC] and water management programs)
• Continuation of waterborne disease research and the creation of best practices for waterborne disease prevention
• Support for public health partner efforts to develop prevention campaigns and disseminate prevention messages
• Education of the public on ways they can protect themselves from waterborne diseases

The health of our nation is closely tied to the safety of our water supply and water systems. The future of waterborne disease prevention will rely on maintaining the public health progress made over the last century while working on solutions and recommendations to protect people from current and future threats.

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