Noroviruses and Drinking Water from Private Wells

What are noroviruses (Norwalk-like viruses)?

Norovirus is the official name for a group of viruses previously described as "Norwalk-like viruses" (NLV). Noroviruses cause the "stomach flu," or gastroenteritis, and have been associated with outbreaks on cruise ships and in communities, restaurants, camps, schools, institutions, and families.

How can I become infected with noroviruses?

Norovirus is highly contagious and is usually spread from person to person. You can become sick after accidentally eating or drinking something contaminated with the feces of a norovirus-infected person. Direct person-to-person contact or contact with contaminated objects or environmental surfaces can also cause illness.

Where and how do noroviruses get into drinking water?

Noroviruses are found in every part of the United States and throughout the world. Noroviruses may be found in water sources, such as private wells, that have been contaminated with the feces of infected humans. Waste can enter the water in various ways, such as sewage overflows or sewage systems that are not working properly.

What are the symptoms of norovirus infections?

The most common symptoms of norovirus infections include nausea, vomiting, diarrhea, and abdominal cramps. Headache and low-grade fever may also occur. Symptoms usually appear within 1 to 2 days after exposure. Most people recover within 2 to 3 days without serious or long-term health effects. However, sometimes people are unable to drink enough liquids to replace the liquids they lost because of vomiting and diarrhea. These persons can become dehydrated (loose too much water from their body) and may need medical attention.

What should I do if I think I have a norovirus infection?

See your health care provider to discuss your concerns.

How is a norovirus infection diagnosed?

Laboratory tests are needed to find out if noroviruses are the cause of illness. These tests will identify the virus in the stools of an infected person. Sometimes these tests are not done unless the laboratory is instructed specifically to look for the organism. Many laboratories are not equipped to test for noroviruses, so a diagnosis is often based on the combination of symptoms and the short time of illness.

What is the treatment for a norovirus infection?

There is no specific treatment available. You should drink plenty of fluids as long as the symptoms persist. Consult with your health care provider.

How do I remove noroviruses from my drinking water?

Heating water at a full boil for 1 minute (3 minutes if you live in a high altitude) will kill or inactivate noroviruses. Water should then be stored in a clean container with a lid and refrigerated.

Because of the small size of the virus, using a point-of-use filter will not remove it from your water.

You may also disinfect your well. Note that noroviruses are moderately resistant to chlorine, so you should contact your local health department for recommended procedures. Remember to have your well water tested regularly after disinfection to make sure the problem does not happen again.

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