(CNN) Even after a hurricane's immediate flooding threat goes away, residents could face a host of potential health problems from the water -- and from what the water leaves behind.

The health concerns that floodwater can bring include physical and mental challenges.

Unhealthy floodwater

Floodwater is more than simple rain. It's often contaminated with sewage and chemicals and can hide sharp objects made of metal or glass. Sewage can cause boils or rashes on parts of the body that are submerged for extended periods of time, such as legs, according to environmentalist Wilma Subra. Chemicals can cause rashes and burning of the skin and eyes after exposure.

Floodwater can also carry disease. That's a serious problem in developing countries where cholera, typhoid or yellow fever are present, according to the World Health Organization . None of those diseases is common in the United States, so an outbreak is highly unlikely.

What may be more common are bouts of diarrhea or other stomach problems if people come into contact with contaminated water or consume food or drink that has. Using items that have been submerged can also cause stomach problems. To cut down on infection, the Centers for Disease Control and Prevention reminds parents not to let children play with toys that have been in the water unless then have since been thoroughly washed.

Exposure to floodwater can increase risk for skin rashes, ear, nose and throat problems and conjunctivitis, but the World Health Organization says that none of these is epidemic-prone. Of 14 major floods between 1970 and 1994, the WHO said , the only major epidemic of diarrheal disease was in Sudan in 1980. American disease control is much more advanced than Sudan's. The other major risk is drinking contaminated water -- but again, US disease surveillance is likely to minimize that risk.

The occasional stomach bug or respiratory infection may be more likely among people having to stay in close quarters with large groups. With a flood, it is hard for people to keep up healthy hygiene standards. When people stay together in shelters with large groups, it's easy to spread germs.

The CDC highly recommends that people who are staying at shelters be extra careful to wash their hands or to use an alcohol hand gel to prevent the spread of disease. People with open wounds also need to take extra care to keep them covered. Floodwater can easily cause a wound to become infected.

Health-related cleanup challenges

Doctors often see more people with 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 Texas can exacerbate asthma or trigger allergies.

The CDC advises people to wear rubber boots and gloves when they clean their homes, to avoid direct contact with any item that has come into contact with floodwater. Subra also recommends a mask or respirator.

Walls, floors and anything with a hard surface that has come into contact with floodwater -- like appliances, countertops or children's play areas -- need to be cleaned with soap and water and disinfected with a bleach solution. 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 a disinfectant. Carpets should be steam-cleaned.

Food and beverages that have come into contact with floodwater should be thrown away. The Food and Drug Administration suggests that people should 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.

Standing water

Floods typically flush out mosquitoes and interrupt their breeding cycle, but when the flooding stops, there is an increased risk of infection from a mosquito-borne illness like Zika or West Nile. Mosquitoes that carry disease thrive in standing water and breed quickly when there is a lot of it.

After Hurricane Katrina, studies showed, areas that were directly impacted saw an increase in cases of West Nile

The CDC suggests that people who are near standing water should take extra care to use bug spray with DEET.

Mosquitoes aren't the only insect, or even animal, to worry about after a storm. Creatures including ants, rodents, reptiles and house pets are displaced. The CDC recommends keeping your distance to avoid being bitten.

Standing water can 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

The biggest health concern from a flood, other than the immediate dangers of rushing waters, may be mental, studies show

Hurricanes and flooding generate additional anxiety, depression and stress. The storms can exacerbate existing mental health problems or lead to new ones.

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Stress is common both during and after any natural disaster. Tears 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. And it may be hard to even accept help, experts say.

Some people may develop problems related to the lingering challenges associated with post-traumatic stress disorder, but the majority of those affected should recover in time. People 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.