Germs That Can Contaminate Tap Water

Key points

  • Public tap water in the United States is regulated and usually safe to drink.
  • However, sometimes tap water gets contaminated with germs that can make you sick.
  • Contact your drinking water utility or health department if you think your tap water is contaminated with germs.
Sink faucet with a drop of water coming out. An inset shows there are germs in the drop of water.

Overview

Report illnesses‎

If you think you got sick from water, report your illness to your health department. Report it even if you do not know what made you sick. Reporting your illness can help your health department find out what caused you to get sick and prevent more illnesses.

Find information below about the germs that most often contaminate tap water and cause disease, and how to remove or control them. Boiling is the best way to kill germs in water.

Cryptosporidium (Crypto)

Common sources

Poop from infected people or animals can get into the water from:

  • Sewage overflows
  • Sewage systems that are not working properly
  • Polluted stormwater runoff
  • Water runoff from farms

Removing Crypto from water

To remove Crypto from drinking water:

  • Boil your water for 1 minute (at elevations above 6,500 feet, boil for 3 minutes),
  • Use a filter certified to remove Cryptosporidium, or
  • Treat water using reverse osmosis, UV light, or ozone

Symptoms of Crypto infection

The most common symptom of Crypto is watery diarrhea.

Keep Reading: About Cryptosporidiosis

Campylobacter

Common sources

Poop from infected people or animals can get into the water from:

  • Sewage overflows
  • Sewage systems that are not working properly
  • Polluted stormwater runoff
  • Water runoff from farms

Removing Campylobacter from water

To remove Campylobacter from drinking water:

Symptoms of Campylobacter infection

  • Diarrhea
  • Fever
  • Stomach cramps
Keep Reading: About Campylobacter infection

E. coli O157

Common sources

E. coli O157 often comes from cattle farms, where it can live in the gut (intestines) of healthy cows. Cow poop containing E. coli O157 can wash into rivers or other water sources from these farms.

Less commonly, poop from an infected person or animal can get into the water from:

  • Sewage overflows
  • Sewage systems that are not working properly
  • Polluted storm water runoff
  • Water runoff from other types of farms

Removing E. coli O157 from water

To remove E. coli O157 from drinking water:

Symptoms of E. coli O157 infection

  • Bloody diarrhea
  • Severe stomach cramps
  • Throwing up
Keep Reading: About Escherichia coli Infection

Enterovirus

Common sources

Poop from infected people can get into the water from:

  • Sewage overflows
  • Sewage systems that are not working properly
  • Polluted storm water runoff

Removing enterovirus from water

To remove enterovirus from drinking water, boil your water for 1 minute. At elevations above 6,500 feet, boil water for 3 minutes.

Disinfectants do not work well to kill enteroviruses and enteroviruses are too small to be removed by most water filters.

Symptoms of enterovirus infection

Symptoms are often mild and commonly include:

  • Fever
  • Runny nose, sneezing, cough
  • Skin rash
  • Mouth blisters
  • Body and muscle aches
Keep Reading: About Non-Polio Enteroviruses

Giardia

Common sources

Poop from infected people or animals can get into the water from:

  • Sewage overflows
  • Sewage systems that are not working properly
  • Polluted stormwater runoff
  • Water runoff from farms

Removing Giardia from water

To remove Giardia from drinking water:

  • Boil your water for 1 minute (at elevations above 6,500 feet, boil for 3 minutes),
  • Use a filter certified to remove Giardia or Cryptosporidium, or
  • Treat water using reverse osmosis, UV light, or ozone

Symptoms of Giardia infection

Diarrhea is the most common symptom.

Keep Reading: About Giardia

Hepatitis A virus

Common sources

Poop from infected people can get into the water from:

  • Sewage overflows
  • Sewage systems that are not working properly
  • Polluted stormwater runoff

Removing hepatitis A virus from water

To remove hepatitis A virus from drinking water:

Hepatitis A virus is too small to be removed by most water filters.

Symptoms of Hepatitis A

  • Dark urine or clay-colored poop
  • Diarrhea
  • Feeling tired
  • Fever
  • Joint pain
  • Loss of appetite
  • Nausea, stomach pain, throwing up
  • Yellow skin or eyes (jaundice)
Keep Reading: Hepatitis A Basics

Legionella

Common sources

Legionella bacteria are found naturally in freshwater environments, like lakes and streams.

The bacteria can become a health risk when they grow and spread in:

  • Building water systems (such as faucets or hot water heaters)
  • Devices that create small drop of water (such as cooling towers, hot tubs, or decorative fountains)

Most illness outbreaks linked to Legionella are in buildings with large, complex water systems. These buildings include hotels, long-term care facilities, and hospitals.

Controlling Legionella in tap water

To control the growth and spread of Legionella in building water systems, owners and managers should:

You can also take steps at home to reduce the growth and spread of Legionella and other germs in your water pipes and devices.

Keep Reading: Preventing Waterborne Germs at Home

Symptoms of Legionella infection

  • Cough
  • Fever
  • Headaches
  • Muscle aches
  • Shortness of breath
Keep Reading: About Legionnaires' Disease

Norovirus

Common sources

Poop from infected people can get into the water from:

  • Sewage overflows
  • Sewage systems that are not working properly
  • Polluted stormwater runoff

Removing norovirus from water

To remove norovirus from drinking water, boil your water for 1 minute. At elevations above 6,500 feet, boil for 3 minutes.

Noroviruses are somewhat resistant to chlorine, so check with your health department about disinfection. Noroviruses are too small to be removed by most water filters.

Symptoms of norovirus infection

  • Diarrhea
  • Throwing up
  • Nausea
  • Stomach pain
Keep Reading: About Norovirus

Rotavirus

Common sources

Poop from infected people can get into the water from:

  • Sewage overflows
  • Sewage systems that are not working properly
  • Polluted stormwater runoff

Removing rotavirus from water

To remove rotavirus from drinking water:

Rotavirus is too small to be removed by most water filters.

Symptoms of rotavirus infection

  • Severe watery diarrhea
  • Throwing up
  • Fever
  • Stomach pain
Keep Reading: About Rotavirus

Salmonella

Common sources

Poop from infected people or animals can get into the water from:

  • Sewage overflows
  • Sewage systems that are not working properly
  • Polluted stormwater runoff
  • Water runoff from farms

Removing Salmonella from water

To remove Salmonella from drinking water:

Symptoms of Salmonella infection

  • Diarrhea (that can be bloody)
  • Fever
  • Stomach cramps
Keep Reading: About Salmonella

Shigella

Common sources

Poop from infected people can get into the water from:

  • Sewage overflows
  • Sewage systems that are not working properly
  • Polluted stormwater runoff

Removing Shigella from water

To remove Shigella from drinking water:

Symptoms of Shigella infection

  • Diarrhea (that can be bloody)
  • Fever
  • Stomach pain
  • Feeling the need to poop even when your bowels are empty
Keep Reading: About Shigella Infection

Resources


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Content Source:
National Center for Emerging and Zoonotic Infectious Diseases (NCEZID)