Flash floods are one of the most damaging natural disasters in the United States, causing over $500 million in damages every year and countless losses of property and life [1].

Water damage in the home can also happen in any home and cause millions of dollars in damages [1]. Even a few inches of water can cause significant and costly damage to a home. 

In this article, we’ll discuss flash floods and what you can do to prepare for one, as well as what to do during it and after.


Flood and water leak statistics and facts:


Floodwaters tend to be more devastating than water leaks, but both can cause substantial damage to your home’s foundation and property. 

Just a few inches of water can cause over $10,000 of damage to your home.

  • From 2015 to 2019, 5.7% of insured homes made a claim. From this number 1.9% made a water damage claim that averaged a little over $11,000 [3].

  • 99% of counties in the United States have been impacted by a flood from 1996 to 2019 [4].

  • According to FEMA, the average flood claim is $52,000 [4].

  • 99% of the United States was impacted by a flood from 1996 to 2019 [4].

6” of water can knock you down, and only one foot of water can float your vehicle and two feet can carry it away—even an SUV or pickup truck [5].

  • A flash flood typically occurs in six hours or less [6].

  • 75% of flash floods occur in late April through mid-September [7].

  • Rising water levels can surge up to one foot in five minutes, and up to 10 to 30 feet [8].

  • Flash floods can tear trees and shrubs apart, roll boulders or vehicles, demolish buildings and bridges and even cause mud and landslides.

  • Almost 50% of flash flood-connected deaths include vehicles [8]

Just 4mph of moving water can move five-foot boulders [8].

What’s the difference between a flash flood and a flood?

Flash floods can be caused by slow-moving thunderstorms or a lot of rainfall that happens over the same area in a short period of time. This can be from a rainstorm, tropical storms or hurricanes. A flash flood is characterized by a sudden and heavy rainfall over a short period of time–usually 3 to 6 hours–and can be incredibly dangerous.

Floods, however, can develop slowly or quickly, but typically happen over a few hours or even days. Flooding can be caused by a burst pipe, improper or lack of natural drainage in your yard, or a leaky washing machine or other appliance.


What is a flash flood?


Flash flooding can occur when there’s too much rain in a short period of time and it isn’t able to properly absorb into the ground. They can also happen if a dam or levee breaks, if a storm drain or lake overflows or even if the ground is too dry.

Many factors determine how severe a flash flood can be:

  • The amount of rain.

  • Where it rains (suburbs vs. urban area).

  • What kind and how much vegetarian is present.

  • The type of soil; rocky soil or clay won’t absorb rain as well as other types of soil.

  • If the earth is already saturated with water or if it’s dry; both are contributing factors to a potential flash flood.


What areas are at risk for flash flooding? 

Cities, in particular, hold a high risk for flash floods due to poor runoff systems created by roadways, parking lots, concrete or other structures that force water to accumulate and flow, instead of being absorbed into the ground. This causes water runoff two to six times more than natural, forested conditions.

If you’ve received a Flash Flood Watch, there are a few areas you should avoid:

  • Low spots, such as underpasses, underground parking garages, basements or anywhere floodwater may collect.

  • Urban areas with a lot of pavement or ongoing construction.

  • Rural areas with steep hills, mountains or sheer valleys.

  • Rocky soil or overly saturated soil. 

  • Parks or forests where a recent burn occurred.

  • Canyons, low river crossings or other water crossings.

 Ultimately, flooding can happen anywhere rainfall suddenly occurs, even on dry soil.


How can floodwater damage your home?


Flood damage is incredibly destructive, primarily due to contaminated water that often comes with flooding. Not only can this type of water destroy items in your home, but it can potentially pose a health hazard.

When water comes from a leaky or burst pipe, it’s generally not contaminated since it has already gone through a filtering process before making its way into your home. So, you may still be able to salvage some of your valuables—though there are always exceptions.


What’s the difference between water damage and flood damage?

Water damage can be from a leaky pipe, plumbing issues or even water overflowing from a toilet or bathtub. On the other hand, flood damage refers to damage from flash floods, storms, overflowing lakes or damage that occurs because of Mother Nature.

Floodwater, on the other hand, runs through the surrounding area and can pick up contaminants and other bacteria that is transported to your home, making the water unsafe to move through or even touch once the items are dry.

Anything that’s touched floodwater or has been submerged for at least 24 hours should be tossed as soon as possible, especially if the items are made of fabric or other porous materials. This includes your furniture, rugs, clothes, towels, etc.

Items you may be able to save might be made of porcelain, glass or hard plastic. Exercise caution when handling these items and thoroughly disinfect them before bringing them back into your home.

If you have any doubt at all that floodwater has touched something, you should dispose of it.


How much can flood damage cost?


Restoring a home after it has experienced flood or water damage is best left to the professionals. They’ll extract the water, dry out the area, remove debris and take out broken or damaged items before starting on the repairs. The average cost to repair water leaks is between $1,000 to $5,000 but depends on the source of the leak and the amount of damage [2]. 

Blackwater is commonly associated with floodwaters or sewage leaks. Not only will you have to pay more for the contamination to be cleaned and treated, but you’ll have to purchase new furniture and appliances, too. For that reason, it’s the most costly type of damage to repair since a lot of your belongings aren’t salvageable.


Mold Remediation $1,500 to $3,500
Clean/Filtered Pipe Water $3.50 to $4.25 per sq. ft.
Greywater $3,000+ or $4.10 to $5.00+ per sq. ft.
Blackwater $20,000+ or $6.25 to $7.25 per sq. ft.

Source: Fixr, How Much Does it Cost [to] Restore Water Damage, September 29, 2021.

What’s the average cost to repair flood damage?

Your cost will depend on various factors, from what type of water damage occurred, to how much water is there, where the damage is located, and whether it’s cosmetic, structural or electrical.


Roof $350 to $1,400
Ceiling $325 to $1,100
Basement $500 to $85,000
Drywall $275 to $785
Flooring $200 to $500
Bathroom Fixtures $150 to $350
Plumbing $1,000 to $4,000

Source: Home Advisor, Water Damage Restoration Cost, January 27, 2022.


Types of water damage and restoration costs

Cosmetic Damage $75 to $1,000
Electrical Damage $300 to $7,000
Structural Repairs $250 to $25,000; though most homeowners pay $500 to $3,000

Source: Fixr, How Much Does it Cost [to] Restore Water Damage, September 29, 2021.

How to prevent water damage in your home?

There are a few methods you can implement inside and outside your property to reduce the chance of water damage or floodwater from damaging your residence.

  • Install smart water detectors to help monitor potential leaks and alert you if they are sensed.

  • Clean gutters every six months, but preferably seasonally.

    • Consider extending your downspouts.

    • Clear out ice dams in winter.

    • Install additional water run-offs, like rain barrels. These ensure that water will fall into the container instead of the ground. 

  • Periodically inspect your roof for cracks, crooked or missing shingles or plant growth.

  • Maintain the sump pump and make sure it’s functioning properly.

  • Ensure your shower and sinks are draining properly. Consider installing drains to catch hair and debris and frequently clean them.

  • When planning your landscaping, you should avoid planting any trees too close to the foundation. We recommend planting things at least 10 to 20 feet away to give the root system enough area to spread.

  • If you live in an area prone to flooding, it’s a good idea to elevate service equipment at least a foot above the ground.

  • Boost or anchor fuel tanks in areas where floods are more common so they aren’t carried away by floodwater.

And remember: Typical homeowners’ insurance doesn’t protect against flood damage, so it’s important that you know your flood risk and purchase flood insurance accordingly. 


Where should you put a water leak sensor?


There are two common ways to help prevent water damage. These include water sensors that detect a leak as it’s happening and an entire water detection system with a shutoff valve.

A water sensor is affordable and easy to install. All you need to do is set it up in a place prone to leaks, and you’ll receive alerts once the sensor detects moisture.

A leak detection system can stop the flow of water but is often costly and complicated to install. 

Here are a few popular places you should consider adding sensors: 

  1. In the attic, next to the windows.

  2. In the kitchen, especially under the sink, below the refrigerator and next to the dishwasher.

  3. In the bathroom, underneath the sink or behind the toilet. 

  4. Next to your washing machine.

  5. On each side of the garage, in order to catch any leaks from potential floods.

  6. In the basement, next to the water heater, or near pipes or windows where floodwater may come in during a flood.

Read more about water leak detectors: Your Guide to Water Leak Detectors, Plus Flood Safety Tips


5 Signs of Water Damage in Your Home


Water damage can happen from many households appliances or from a leaky pipe, clogged gutters or septic tank overflow.

Here are five common ways water damage can happen in your home, and what you should be on the lookout for to help prevent further damage:

  1. A sudden increase in your monthly water bills can be caused by a leaky pipe.

  2. If drywall or paint starts to suddenly flake, crumble or crack.

  3. Be wary about an ongoing leak if you encounter pools of water that keep coming back after you clean them.

  4. Discolored, wet or dripping spots on the ceiling or walls could tell you that there was previous water damage or an outstanding issue.

  5. If you smell any kind of musty, damp or “off” moldy smell accompanied by mold.

If you’ve noticed any of the above, you should speak to a professional immediately. 


ADT flood sensors can notify you of water damage


Adding flood detectors to your home is just one step in helping to keep your home safe from water damage. Knowing what causes flash floods and water damage means you can continue to keep an eye on potential leaks in your home.

ADT can help give you peace of mind while professionally monitoring your home for floods, intruders and more.


Frequently Asked Questions about Floods

Am I required to have flood insurance?

If you live in a high-risk Special Flood Hazard Area (SFHA) and have a federal mortgage, flood insurance may be required for your home. 


How much does flood insurance cost?

The average annual flood insurance policy is around  $700 or about $58 per month. The price is dependent on several factors:

  • Where your home is located.

  • If you live in a flood risk zone.

  • The age and design of the residence.

  • What kind of foundation your home has and what kind of residence you live in, such as a one-family home, two-family home, etc.

  • If your structure is a residential or commercial property.

  • The kind of coverage and deductible you choose.

Does car insurance cover flood damage?

Yes, car insurance can include flood damage as long as you opt for a comprehensive auto plan.  


What types of flash flood warnings are there?

There are three main flash flood warnings: Flash Flood Watch, a Flood Advisory and a Flash Flood Warning.


  • A Flash Flood Watch means that the current weather conditions are favorable for a flash flood, but that it may not necessarily happen. Keep an eye on changing weather conditions and be prepared for action. 

  • A Flood Advisory is issued if a minor flood is expected to occur, but it’s not expected to reach flash flood levels. If you’re living in a low-lying area or driving during this time, you should take extreme caution and continue to monitor the situation.

You should never drive on a flooded road.

  • Flash Flood Warning is delivered when a flash flood is going to happen or is already happening in your area. This is a potentially life-threatening situation, so you should move to higher ground, especially if you’re near a low-lying area.

When is flash flood season?

Certain parts of the U.S. experience “monsoon season” every year, typically from June to September. A monsoon typically brings in precipitation and wind into dry climates that aren’t prepared for sudden rainfall. If the ground is hard and overly dry, it can act like a concrete surface, propelling water along the ground instead of getting absorbed.

The states most affected by this include New Mexico, western Texas, parts of southern Utah, Arizona, Colorado and southern Nevada. 


What other kinds of water damage can happen around a home, other than flood damage?

Water damage from a leaky pipe is going to be the cheapest fix. Since the water is typically filtered, it’s less likely to have contamination you’d find in greywater or floodwater.

Greywater comes from pipes connected to your washing machine or shower and can also come from bathtubs or sink flooding. It may have some soap or cleaning products in the water that won’t necessarily make you sick, but may still irritate your skin.


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