Greater depths of flooding cause more damage

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The damage caused by flooding varies based on depth. Higher depths of floodwater typically cause greater and more costly damage to a home.

Without free access to accurate flood information, more Americans will unknowingly be at risk from the nation’s costliest natural disaster. By making flood risk data freely available for all, individuals and communities can prepare for and mitigate risks before they become a reality. Search your property on to learn if your home is at risk.

Flood water depths

The depth of floodwater has a big impact on what could be affected in a flood, as even a few inches of water can cause major damage and require costly repairs or replacement of items. The longer a flood lasts, the more damage it can cause, and can increase the risk for mold.

Outside, flood water poses a serious threat to transportation and public infrastructure. Just 6 inches of moving water can knock over an adult, and 12 inches can carry away a small car. A good rule of thumb is to never drive through flood water deeper than the center of your vehicle’s wheels.

Common impacts

6 inches of water


Flooded yards can lead to rotten roots and other health issues for plants and standing water can attract insects like mosquitoes. 

Drywall, exposed insulation, wallpaper
Water damages most drywall, and can cause the paper facings to mold. Most insulation will need to be replaced if it gets wet, as water causes it to compress and lose its ability to insulate. 

Wood floors, carpets
After a flood, many floor types may need to be replaced. Carpet and padding can become too difficult to clean, laminate flooring can peel apart, and hardwood floors are likely to warp or rot.

6+ inches of water


Most cars unable to drive
Six inches of water is enough to reach a car’s exhaust and cause stalling. It can also cause tires to lose traction and slide.

Insulated appliances 
When flood water is above six inches it can damage the electrical components or penetrate the insulation of appliances such as refrigerators and ovens, requiring replacement.

1 foot+ of water


Furnaces, HVAC systems
Flood water can corrode or contaminate heating and cooling systems, requiring replacement.

Electrical outlets
Most wall outlets are typically located 12-16 inches above the floor. If any water reaches an electrical outlet, it should be replaced as soon as it is safe to do so.

Cars float
It only takes a foot of water to float most cars and severely damage their engines.

2 feet+ of water


Trucks float 
A pickup truck or SUV can be carried away by only a couple feet of water.

Large appliances 
Enough flood water can damage the inner workings of appliances such as washers, dryers and dishwashers. Unlike insulated appliances, these may be repairable.

3 feet+ of water



Building’s infrastructure
More than three feet of flooding can cause severe damage to a home's infrastructure, including its foundation and framework. This level of flooding can cause damage too severe to repair. 

Water supply, sewage, plumbing systems
Outside, water can cause lasting damage to water wells as well as sewage and plumbing systems.

Flood damage costs

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The cost of flood damage depends on its severity and can include structural repairs, replacement costs, water removal, cleanup, ventilation, and decontamination.

Cost Factors

  • The size and extent of damage
  • The type of water damage (clean water, grey water, or black water)
  • The materials or items being replaced or restored
  • The local market (cost of labor and materials, building code consideration)

The National Flood Insurance Program provides an estimation tool for homeowners. 

Learn more 

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