Even after a hurricane’s immediate flooding threat goes away, residents could face a host of potential health problems from the water — and what it leaves behind.
Floodwater is more than just rain. It’s often contaminated with sewage, bacteria and chemicals. Sharp objects made of metal or glass can also hide in the murky water.
Exposure to floodwater contaminated with sewage can irritate the skin, leading to boils or rashes, particularly on parts of the body that are submerged for any extended period of time, according to environmentalist Wilma Subra. Although brief skin contact with floodwater shouldn’t be a problem, even a minor cut or scrape can be an entry point for harmful bacteria and viruses.
Chemicals in floodwater can also cause rashes and burn the skin and the eyes after exposure.
Sickness from floodwater
Floodwater can carry disease. That’s a constant problem in developing countries where conditions like cholera, typhoid or yellow fever are present, according to the World Health Organization. However, none of these diseases is common in the United States, so that kind of outbreak is highly unlikely.
What’s more common in the US are bouts of diarrhea and other stomach problems after people come into contact with contaminated floodwater, or if they eat or drink something that has. Floodwater can contaminate drinking water, especially from private wells, the US Centers for Disease Control and Prevention said. Those wells need to be tested before using if they come into contact with floodwater.
For municipal water, state and local health departments will make recommendations about whether it needs to be boiled or treated before using.
Using items that have been submerged in floodwater can also cause stomach problems. To prevent illness in children, the CDC highly recommends that parents don’t let their kids play with toys that have been in the water unless they’ve been disinfected with a solution of one ounce of bleach — about 1/8th of a cup — in 2 gallons of water.
Exposure to floodwater can increase a person’s risk of ear, nose and throat problems, several studies have shown, but most of these problems involve individual cases and do not turn into epidemics, according to WHO. Of 14 major floods between 1970 and 1994, WHO says, the only major epidemic of diarrheal disease was in Sudan in 1980.
The occasional stomach bug or respiratory infection may be more likely among people who have to stay in close quarters with large groups. In flood conditions, it’s hard for people to keep up healthy hygiene standards, and when people stay together in shelters with large groups, it’s easy to spread germs.
The CDC recommends that people staying in shelters be extra careful and regularly wash their hands or use alcohol-based hand sanitizer to prevent the spread of disease.
Health-related cleanup challenges
Doctors often see more respiratory infections after floodwaters recede and people are allowed to return to their homes. Contamination from floodwaters and the mold that quickly grows in a warm environment like those in Florida or Georgia can exacerbate asthma or trigger allergies.
The CDC advises wearing rubber boots and gloves when cleaning up homes and avoiding direct contact with any item that has been in floodwater. Experts also recommend wearing a mask or respirator.
If floodwater has entered a home, dry it out as soon as possible to prevent mold. If it has stopped raining, open windows and doors to speed the process. Use dehumidifiers if there is power, and put fans at doors and windows to blow air out, rather than inward, so it doesn’t spread mold.
Walls, floors and anything with a hard surface that has come into contact with floodwater — like appliances, countertops or children’s play areas — needs to be cleaned with soap and water and disinfected with a bleach solution. If walls or floors need to be replaced or refinished, the Environmental Protection Agency says, everything needs to be thoroughly cleaned and dried to prevent mold growth.
Fabrics should be washed in hot water or dry-cleaned. Furniture like beds and upholstered sofas and chairs that can be saved should be dried in the sun and then sprayed with disinfectant. Carpets should be steam-cleaned.
Food and beverages that have come into contact with floodwater should be thrown away. The US Food and Drug Administration suggests that people also throw away prescription drugs – even those that are in their original containers or with screw tops – as they may no longer be safe if they’ve come into contact with contaminated water.
Risks from standing water: animals and electrocution
Floods typically flush out mosquitoes and interrupt their breeding cycle, but when the water recedes, there is an increased risk of infection with a mosquito-borne illness like West Nile or, as one 2019 study showed, Zika.
Mosquitoes that carry disease thrive in standing water and breed quickly when there is a lot of it. After Hurricane Katrina, for example, areas that were directly affected saw a sharp increase in cases of West Nile.
The CDC suggests that people who are working or living near standing water take extra care to use bug spray with DEET or picaridin. Wear long sleeves, pants and socks outdoors, even if it is warm, to prevent mosquito bites.
Mosquitoes aren’t the only insect – or even the only animal – to worry about after a storm. When snakes get displaced by a flood, they often look for shelter and food closer to people than they usually would. Flood-damaged structures can be a magnet for snakes because it’s easier for them to get in and hide under debris.
Wildlife specialists recommend wearing snake-proof boots at least 10 inches high, and people cleaning up debris should grab it from the top if possible rather than placing fingers underneath.
Other creatures that may be displaced by floods include ants, rodents, spiders, reptiles, alligators and even household pets. The CDC recommends trying to keep your distance to avoid being bitten.
Standing water can also be electrically charged due to fallen power lines that are submerged or those that are underground but still live. With this comes a risk of electrocution.
Mental health concerns
Still, other than rushing water, the biggest health concern from a flood may be mental, studies show.
Hurricanes and flooding generate anxiety, depression and stress. Storms can exacerbate existing mental health problems or lead to new ones.
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Stress and emotional distress are common during and after any natural disaster. Crying may come easier, sleep may be a challenge, worry or a desire to be alone may be especially strong, thinking may become muddled, and it may be hard to remember things or to listen to people. It might also be hard to accept help, experts say.
Some may develop problems related to the lingering challenges associated with post-traumatic stress disorder, but the majority of those affected should recover in time.
Human nature is resilient, and most people can adapt over time after a disaster, experts say. Those who have strong bonds with family, friends and co-workers tend to recover best, so experts suggest paying close attention to those relationships to help speed recovery.
For those with lingering mental challenges, counseling is recommended. The federal government offers a Disaster Distress Helpline to help those struggling with mental health problems resulting from a storm. That toll-free number, staffed by mental health professionals, is 1-800-985-5990.
Studies show that suicide can also be a risk after a natural disaster. The 988 Suicide and Crisis Lifeline provides free emotional support to people in mental health crises and connects them to local resources. The line operates 24 hours a day, seven days a week, and comprises over 200 local crisis centers across the country.