Flooding and Health

Ninety percent of all natural disasters in the United States involve flooding. One-in-100-year flooding can now be expected every eight years! Flooding is both an environmental emergency and a longitudinal health event. For physicians, the clinical consequences extend well beyond the immediate disaster period. Because many flood-related harms are preventable, clinicians have an important role in anticipatory guidance, early recognition, and coordination with public health and emergency response systems. Flood events can disrupt nearly every determinant of health at once: housing, sanitation, transportation, access to care, continuity of medications, food safety, potable water, electricity, and social support. The clinical pattern depends on the type of flooding, duration of water exposure, level of sewage or chemical contamination, displacement, ambient temperature, and the resilience of local infrastructure. Flash floods may produce sudden drowning and trauma, while prolonged inundation may drive mold growth, vector exposure, gastrointestinal illness, and delayed mental health effects.

The most urgent flood-related threats are drowning, hypothermia or heat illness, electrocution, crush injury, falls, lacerations, puncture wounds, and motor vehicle trauma. Even shallow moving water can be dangerous, and flooded roadways remain a major preventable source of death and injury. In the clinical setting, physicians should ask specifically about submersion, water ingestion, electrical exposure, contaminated wounds, delayed evacuation, and cleanup activities.

Wound evaluation deserves particular attention. Floodwater may contain sewage, soil, sharp debris, animal waste, chemicals, and microorganisms. Clinicians should irrigate and debride wounds when indicated, assess for retained foreign bodies, review tetanus immunization status, and provide empiric antibiotics when clinically appropriate for high-risk wounds, deep tissue injury, immunocompromised patients, or signs of infection.

Flooding does not automatically produce infectious outbreaks, but it creates conditions that increase risk: contaminated water, crowding in shelters, disrupted sanitation, delayed wound care, and reduced access to routine medical services. Common presentations include gastroenteritis, skin and soft-tissue infection, conjunctivitis, otitis externa, respiratory infections, and infected wounds. Depending on geography and exposure, clinicians should also consider leptospirosis, mosquito-borne infections, and other locally relevant pathogens. When evaluating febrile illness after flooding, exposure history is essential: contact with floodwater, occupational or volunteer cleanup, animal exposure, rodent exposure, ingestion of untreated water, shelter residence, travel, and timing of symptoms. Physicians should coordinate with local public health authorities when clusters, unusual pathogens, or waterborne illness are suspected.

Water-damaged buildings can develop mold within days, particularly when porous materials remain wet. Mold and damp indoor environments can worsen asthma, chronic obstructive pulmonary disease, allergic rhinitis, and hypersensitivity symptoms. Counseling should emphasize appropriate respiratory protection during cleanup, discarding materials that cannot be cleaned and dried, and avoiding occupancy until moisture and mold have been adequately addressed.

Floodwater may mobilize household chemicals, fuel, pesticides, industrial waste, sewage, and debris. Disasters bring salt and freshwater organisms to areas, can spread materials from sewers, toxic cleanup sites, and animal feed lots. Exposure can occur through skin contact, inhalation, ingestion, or contaminated food and water. Physicians should consider toxic exposure when symptoms are nonspecific, clustered among household members, or temporally related to cleanup, generator use, or reentry into a damaged building.

Carbon monoxide poisoning is a recurrent post-flood hazard when generators, pumps, grills, pressure washers, or fuel-burning equipment are used indoors, in garages, or near windows and doors. Headache, dizziness, nausea, weakness, confusion, chest pain, or syncope in multiple household members should prompt immediate consideration of carbon monoxide exposure. Physicians should advise patients to use fuel-powered equipment only outdoors and well away from enclosed spaces.

Flooding often destabilizes chronic disease management. Patients may lose medications, monitoring supplies, durable medical equipment, refrigeration for insulin or biologics, access to dialysis, oxygen, mobility aids, wound care supplies, or transportation to appointments. Physicians should proactively identify patients with high dependency on continuous therapy and develop contingency plans for refills, replacement devices, remote contact, and alternate care sites.

Conditions that commonly worsen after displacement include diabetes, hypertension, heart failure, chronic kidney disease, asthma, COPD, seizure disorders, pregnancy complications, substance use disorders, and serious mental illness. Flood response should therefore include both acute triage and continuity planning, especially for patients who rely on electricity, refrigeration, home health services, or frequent clinical monitoring.

Flooding can produce acute stress, grief, insomnia, anxiety, depression, substance use relapse, and post-traumatic stress symptoms. (More on Mental Health and Climate Change in next month’s blog.)

Clinical encounters after floods should include practical questions: Where are you sleeping? Do you have safe water and food? Can you obtain medications? Is your home dry and safe to enter? Do you have electricity for medical devices? Are you able to get to follow-up appointments? These questions can uncover health risks that may not appear in a symptom-focused history.

Some populations are at increased risk. Equity-centered care means tailoring advice to the patient’s resources and constraints. A patient may know not to enter floodwater but still need to retrieve medication, check on family, or return to unsafe housing. Physicians can improve outcomes by documenting medical needs for emergency services, supporting prescription replacement, coordinating with shelters, and linking patients to local recovery resources.

Conclusion
Flooding is a clinical, environmental, and social emergency. Physicians can reduce harm by anticipating predictable risks, asking targeted exposure questions, protecting vulnerable patients, maintaining continuity of chronic disease care, recognizing delayed complications, and reinforcing clear safety messages. The most effective medical response begins before the water rises and continues long after floodwaters recede.

References
Aldrich N, Benson WF. Disaster Preparedness And The Chronic Disease Needs of Vulnerable Older Adults. Prev Chronic Dis 2008;5(1).

Centers for Disease Control and Prevention. Floods and Your Safety. Updated March 16, 2026.

Centers for Disease Control and Prevention. Safety Guidelines: Floodwater. Updated February 6, 2024.

Centers for Disease Control and Prevention. Mold Clean Up Guidelines and Recommendations. Updated February 16, 2024.
Core Disaster Life Support, v.3.0.

https://ars.els-cdn.com/content/image/1-s2.0

https://www.thelancet.com/journals/lanmic/article/PIIS2666-5247(24)00039-9/fulltext?s=09

U.S. Environmental Protection Agency. Mold Cleanup. Updated April 21, 2026.

U.S. Environmental Protection Agency. Homeowner’s and Renter’s Guide to Mold Cleanup after Disasters. Updated February 18, 2026.

Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health. Staying Safe After the Storm: Health and Safety Messages for Employers, Workers, and Volunteers. Posted August 5, 2025.

National Oceanic and Atmospheric Administration. Use Caution After Storms. Updated April 30, 2026.

National Institute of Environmental Health Sciences. “Hidden effects of floods” linked to higher death rates. February 2025.