Water and Sanitation Safety and Risks After a Hurricane

As millions of people in the Southeast continue to live under a boil water advisory following Hurricane Helene, and now with Hurricane Milton set to be one of the most destructive in history, Rollins School of Public Health experts offer information about water and sanitation safety.

In this interview, Christine Moe, PhD, Eugene J. Gangarosa Professor of Safe Water and Sanitation and director of the Center for Global Safe WASH, explains the water and sanitation challenges that can follow a hurricane and what people can do to stay safe. Thomas F. Clasen, PhD, Rose Salamone Gangarosa Professor of Environmental Health, provides additional insights about storing water ahead of time and filtering water after the fact. And Marlene Wolfe, PhD, assistant professor of environmental health, discusses the dangers of contaminated flood waters.

Moe urges people in communities impacted by hurricanes to follow the guidance provided by their state health departments during this emergency. Those in North Carolina can review the information from the North Carolina Department of Health and Human Services about ensuring water safety after Hurricane Helene.

It’s important to remember that while the risk of unsafe drinking water is problematic, the greater risk of physical injury and death are due to storm surge, flooding, wind, and accidents. 

Many people lack reliably clean running water in the wake of Hurricane Helene and many more could also face these conditions after Hurricane Milton hits. What are the biggest disease risks associated with not having running water for weeks on end?

MOE: The greatest risks are from two categories of diarrheal diseases:

1. Diseases from drinking contaminated water that may contain sewage and animal fecal contamination. These are a mix of diseases due to:
   1. Bacteria such as toxin-producing coli and Shigella (the cause of bacillary dysentery).
   2. Protozoa including giardia and cryptosporidium.
   3. Viruses including norovirus (cause of the “stomach flu”) and hepatitis A virus.
2. Diseases from poor hygiene because people don’t have enough water to wash their hands and food. These diseases are going to be the same as I noted above.

What is the difference between potable and non-potable water? What can each be used for?

MOE: Potable water is usually defined as safe for drinking, but you also need potable water for other domestic and personal hygiene purposes such as food preparation, baby formulas, making ice, brushing teeth, and washing your face. In other words, any water that may be ingested.

For childcare, it is important that babies and young children do not ingest contaminated water while bathing. It is safer to give them a sponge bath.

It is also important to ensure that open cuts, wounds, and burns are not exposed to contaminated water because they may become infected.

Non-potable water is usually used for industrial purposes, but can be used for toilet flushing, irrigation, and some cleaning purposes such as washing floors.  It really depends on how clean or contaminated this water is.

What actions can people take to stay safe when they don’t have access to clean water?

WOLFE: Water for drinking, cooking, brushing teeth, or anything that touches your face or is ingested should be treated before use. The most accessible option to most people will be boiling. Chemical treatment, such as adding chlorine tablets or diluted bleach, can also be a good treatment option but should be done based on instructions from local officials or based on product packaging inserts. 

Boiling water requires a significant amount of fuel. In order to make water safe to drink, water should be at a rolling boil for at least one minute (three minutes if above 5,000 ft elevation). Purchasing or procuring bottled or packaged water that is safe to drink is a good option, if possible, for this reason.

MOE: Household water treatment options include boiling water if possible.

• Boiling water can effectively kill microbes (“germs”) in water that can cause disease.
• Boiling is not effective against potential chemical contaminants in the water. Using a Brita-type filter with granular activated carbon may help remove or reduce some chemical contaminants as a short-term solution. Filter and boil the water first, then allow to cool before pouring into a Brita-type pitcher.
• If the water is cloudy, it is important to try to filter it first (for example, through a paper coffee filter, clean dish towel, or paper towel) before boiling.

CLASEN: As gas and electricity can be interrupted, however, it is advisable to safely store drinking water in advance or to purchase drinking water, if possible.

MOE: Careful use of bleach can help in some circumstances:

• Bleach can be added to water used for cleaning surfaces. I don’t recommend adding it to make water safe to drink because bleach usually contains other chemicals in addition to sodium hypochlorite.
• Guidance from the Centers for Disease Control and Prevention (CDC) states that unscented household bleach can be used for emergency water treatment and provides instructions here on how to do this.

CLASEN: Only filters rated as “microbiological purifiers” (level 3) can be relied on for temporary treatment of drinking water. Treated water should also be used for washing fruits and vegetables and cooking. Unless supplies are adequate, you don’t need to use treated water for handwashing or personal hygiene except when it may be ingested, such as teeth brushing.  

WOLFE: Yes, for bathing it is okay to use water that is not high quality enough for drinking—but be sure to use soap.

MOE: And alcohol-based hand sanitizers, alcohol hand wipes, and bleach wipes are useful for personal hygiene and cleaning when there is no water available for washing. The wipes provide the advantage of physical removal of dirt and germs from hands as well as disinfection. However, some germs like norovirus are not killed by alcohol-based hand sanitizers.

Are there any other water and hygiene risks after a hurricane?

WOLFE: Flood waters are highly contaminated and should be avoided. As floodwaters recede, items that were submerged will also be contaminated, so caution should be taken when clearing out debris. This includes wearing personal protective equipment like gloves, masks, and goggles.