How Floods Affect Health

Flooding is catastrophic in every way, from property and infrastructure damage to loss of life and wider health consequences. As flooding becomes more common for more people in a warming world, we examine the effects on human health. Flooding is the most common natural disaster worldwide, affecting over two billion people between 1998 and 2017 and accounting for 44% of disasters worldwide. As climate change makes the world more vulnerable to extreme weather events, more people are likely to be affected by flooding and its devastation, including serious health consequences.

How can a flood affect your health?

The health consequences of natural disasters such as flooding are complex and cascading and can simultaneously affect any person or population. Floods can have an immediate and long-term impact on human health, both directly and indirectly. Furthermore, the health of communities that have experienced flooding is jeopardized. Responders to disasters, healthcare professionals, property restoration teams, and critical service providers may all be impacted. When natural disasters such as floods strike, much attention is paid to the economic impact, property damage, and human casualties. However, in many ways, these overlap with health concerns.

Flooding can strain health services due to damaged infrastructure, a loss of health professionals, and a lack of access to medicine, potentially delaying care or treatment for those in need. The economic fallout or loss of possessions and livelihoods caused by a flooding disaster can result in financial insecurity, which can impact mental health, not to mention the grief of losing loved ones. The following is a list of common flood-related health effects.


In the event of flooding, diseases, and outbreaks are another primary health concern. These can manifest as waterborne diseases caused by drinking or coming into contact with contaminated water. Diarrhea, cholera, typhoid fever, and leptospirosis are examples. It can also be a vector-borne disease transmitted by an intermediate species carrying the disease pathogen, such as a mosquito. Dengue fever and malaria are two vector-borne diseases caused by flooding. After floodwaters recede, stagnant water left behind in gardens, parts of the home or even farming lands can serve as a breeding ground for mosquitoes, leading to diseases such as dengue or malaria.

Mental Health

Mental health issues, which can arise later, are frequently overlooked and understudied compared to the immediate health effects of flooding. So far, it is known that the experience of surviving a flooding disaster can impact people here long after the event, sometimes for many years. Anxiety, depression, post-traumatic stress disorder (PTSD), psychosis, and insomnia are all common mental health issues that arise in the aftermath of a flood. The clean-up, recovery, and rebuilding process can be stressful, especially if it is not well managed by the government and the private sector.


Although evidence to the contrary, undernutrition or malnutrition is another health impact that can result from flooding disasters, flood victims are known to eat less during or after flooding and frequently lose access to regular food supplies. Flooding can also significantly disrupt food systems such as agriculture. This can impact the quantity and quality of food, resulting in food insecurity and undernutrition.


Warmer temperatures can increase precipitation and cause extreme weather events, exacerbating flooding. Adapting will be critical in dealing with the health effects of flooding and mitigation efforts such as emission reductions. Flooding’s health consequences will only worsen unless the world takes decisive and swift action to address climate change.