Waterborne Illness

How Prevalent is Waterborne Disease in the United States?

The Centers for Disease Control and Prevention (CDC) plays an active role in monitoring and surveillance of diseases spread through any water source in the United States. The following estimates were published for 17 waterborne pathogens in 20141:

  • 15 million illnesses.
  • 601,000 emergency department visits.
  • 118,000 hospitalizations.
  • 6,630 deaths.
  • $3.33 billion in direct healthcare costs for emergency department visits and hospitalizations.
  • 1 in 44 people will get sick annually from waterborne diseases.

The next few charts illustrate the top five diseases acquired from waterborne pathogens and how they impact healthcare in the United States1:

  • Top five diseases by number of cases:
    • Otitis externa (swimmer’s ear): 4,7 million
    • Norovirus infection: 3 million
    • Giardiasis: 415,000
    • Cryptosporidiosis: 322,000
    • Campylobacteriosis: 171,000
  • Top five diseases causing the most emergency department visits:
    • Otitis externa (swimmer’s ear): 567,000
    • Norovirus infection: 26,300
    • Nontuberculous mycobacterial infection: 5,080
    • Legionnaires’ disease: 667
    • Giardiasis: 567
  • Top five diseases causing hospitalizations:
    • Nontuberculous mycobacterial infection: 51,400
    • Otitis externa (swimmer’s ear): 23,200
    • Pseudomonas pneumonia: 15,500
    • Legionnaires’ disease: 10,800
    • Pseudomonas septicemia: 5,590
  • Top five diseases causing the most deaths:
    • Nontuberculous mycobacterial infection: 3,800
    • Legionnaires’ disease: 995
    • Pseudomonas pneumonia: 730
    • Pseudomonas septicemia: 695
    • Otitis externa (swimmer’s ear): 219
  • Top five diseases with the highest total direct healthcare costs:
    • Nontuberculous mycobacterial infection: $1.5 billion
    • Otitis externa (swimmer’s ear): $564 million
    • Pseudomonas pneumonia: $453 million
    • Legionnaires’ disease: $402 million
    • Pseudomonas septicemia: $214 million

Can Our Drinking Water Spread Disease? The Answer is Yes!

The CDC published surveillance summaries in March 2024, of waterborne disease outbreaks associated with drinking water in the United States between 2015 and 2020 using the National Outbreak Reporting System (NORS)2. NORS collects voluntary reports from public health departments of enteric disease outbreaks caused by bacterial, viral, parasitic, chemical, toxin, and unknown agents. Data collected includes2:

  1. The number of cases, hospitalizations, and deaths.
  2. The etiologic agent, either suspected or confirmed.
  3. The impacted type of water system such as community, individual, or private systems.
  4. The setting of the exposure such as hospital, hotel, lodge, private residence, restaurant, camp, amusement parks, universities, etc.
  5. Epidemiologic and environmental data to describe the outbreak.

Each year in the United States, waterborne pathogens cause an estimated 7.15 million illnesses, 118,000 hospitalizations, and 6,630 deaths, resulting in $3.33 billion in direct health care costs3.

NORS Results

Public health departments from twenty-eight states voluntarily reported 214 outbreaks associated with drinking water with the following etiologies2:

  1. 87% (187 outbreaks) biofilm associated
  2. 11% (24 outbreaks) enteric illness associated
  3. 1% (2 outbreaks) unknown
  4. 1% (1 outbreak) chemical or toxin associated

More concerning, 172 outbreaks were linked to water from public water systems2. Individual or private water systems were also implicated as sources of outbreaks. Drinking water-associated outbreaks resulted in these findings2:

Type of Water System # Cases of Illness # Hospitalizations # Deaths
Public 2,140 563 88
Individual, Private 944 52 14

Biofilm Associated Outbreaks

Biofilms are microbial communities that attach to moist surfaces such as water pipes and provide nutrients for pathogens, such as Legionella to grow and thrive2. Biofilm pathogens are difficult to control because they resist water treatment processes. Exposure can occur from drinking the water or by inhaling aerosols from fixtures such as showerheads and humidifiers2.

Most biofilm-related outbreaks implicated Legionella (98%) whereas two nontuberculous mycobacteria (1%), and one Pseudomonas outbreak (1%) comprised the remaining outbreaks2. Outbreaks caused by Legionella caused 786 cases of illness, 544 hospitalizations, and 86 deaths and was most implicated in public water system outbreaks2.

Legionella is a waterborne bacterium that causes Legionnaires’ disease, a serious type of pneumonia. Legionnaires’ disease is on the rise in the United States5. As a response to the rise in Legionnaire’ disease, the CDC created a toolkit for implementing industry standards for developing a water management program to reduce the growth and spread of Legionella5.

Drinking water exposures are associated with 40% of hospitalizations and 50% of deaths and are primarily linked with biofilm pathogens such as Legionella and nontuberculous mycobacteria (NTM), costing the United States $1.39 billion annually4.

Enteric Associated Outbreaks

Enteric associated pathogens were responsible for 1,299 cases of illness, 2% hospitalizations, and no deaths2. The prominent pathogens were Campylobacter, Cryptosporidium, Escherichia coli, Giardia, norovirus, and Shigella2.

Enteric outbreaks are primarily linked to wells and were reported from mobile home parks, amusement parks, farms, camps, and private residences2.


Surveillance is essential to monitor waterborne disease prevalence and to detect outbreaks related to drinking water. Prevention strategies are critical to prevent the emergence of biofilm-associated disease which is the major cause of waterborne illness. The CDC offers a toolkit for developing a water management program to reduce the growth and spread of Legionella in buildings5. Drinking water regulations and water management programs are essential to controlling all pathogens to prevent all waterborne illnesses.

DTPM’s Mission

DTPM’s mission is to help laboratories with testing supplies for the detection of bacterial and viral agents. The DTPM Gastrointestinal (GI) Test Kit and the DTPM Respiratory Test Kit are molecular test kits that may aid in the detection of infectious agents**. DTPM also offers DNA/RNA purification kits to extract DNA/RNA from biological samples prior to molecular testing. General testing supplies such as gloves, lint-free wipes, molecular testing supplies, and pipette tips are also available on the DTPM store. Contact us today to learn how DTPM can help your laboratory reduce costs and  achieve efficient operations.

**For Research Use Only. Not for use in diagnostic procedures.


  1. https://www.cdc.gov/healthywater/surveillance/burden/findings.html
  2. US Department of Health and Human Services | Centers for Disease Control and Prevention | MMWR | March 14, 2024, | Vol. 73 | No. 1
  3. Collier SA, Deng L, Adam EA, et al. Estimate of burden and direct healthcare cost of infectious waterborne disease in the United States. Emerg Infect Dis 2021;27:140–9. PMID:33350905 https://doi. org/10.3201/eid2701.190676
  4. Gerdes ME, Miko S, Kunz JM, et al. Estimating waterborne infectious disease burden by exposure route, United States, 2014. Emerg Infect Dis 2023;29:1357–66. PMID:37347505 https://doi.org/10.3201/ eid2907.230231
  5. https://www.cdc.gov/legionella/downloads/toolkit.pdf