Flooding: What to Do Before, During, and After
Flooding is a very common natural phenomenon characterized by a temporary overflow of water onto normally dry land. It can happen slowly or very quickly. Flash floods can come without warning or rain in the forecast. Flooding poses a significant threat in many regions of the United States and its territories throughout the year. Failing to evacuate flooded areas or entering flood waters can lead to injury or death.
Flooding: Prone Areas and Potential Damage
Areas Prone to Flooding
These areas have a larger amount of pavement which prevents excess water from being absorbed into the soil.
Historical data shows these areas file more flood-related insurance claims compared to other regions.
Here, storms come ashore from the ocean causing extreme rainfall and high tides can bring in more water than usual.
Flash floods can occur as excessive rainfall causes runoff to suddenly join streams or other channels that are normally dry.
Damage Caused by Flooding
High waters can inundate substations where electricity is distributed, damaging equipment. Utilities often shut power down as a preventative measure resulting in an outage as well.
Flooding can cause a weakening of a building’s foundation and structural integrity and significantly damage its exterior, interior, electrical systems, insulation, and finishes.
Flooding can cause extensive damage to roads and disrupt the transportation of passengers, goods, and services.
Before a Flood Happens
Sometimes forecasters can anticipate flooding and the areas that will be impacted. Other times flash flooding can occur within minutes and without any warning or even sign of rain. Being prepared ahead of time can save your life and offer peace of mind.
#1 Knowing your flood risk
Start by checking FEMA’s Flood Map Service Center to see whether your home is in a mapped flood zone. This can tell you if your property is in a high-risk, moderate-risk, or low-risk area according to FEMA’s current flood maps.
However, these maps are not a guarantee that flooding will or will not happen. Even homes outside high-risk zones can flood, so it is wise to consider local drainage problems, nearby creeks or low spots, past neighborhood flooding, and changing weather patterns when making your plan.
To check whether your home is located in a mapped flood hazard area, visit the FEMA Flood Map Service Center and enter your address. While this tool can't prodict your exact personal flood risk, it can help you view your official flood map and better understand your area’s flood risk.
#2 Flood Insurance
Flood insurance is most important for homes in high-risk flood zones, near rivers, creeks, coastlines, storm drains, low-lying areas, or places with a history of flooding. However, it can still be worth considering for homes outside high-risk zones because standard homeowners insurance usually does not cover flood damage, and flooding can happen in many areas after heavy rain, poor drainage, rapid snowmelt, storm surge, or overwhelmed local infrastructure.
Most standard homeowners and renters insurance policies do not cover flood damage, so a separate flood insurance policy is usually needed. Flood coverage is available through the National Flood Insurance Program (NFIP), and in some areas through private insurers as well. In most cases, there is a 30-day waiting period before an NFIP policy goes into effect, so the best time to buy is well before a flood threat or disaster occurs.
#3 Protecting your home
- Lift It or Lose It: If you live in an area at risk for flooding, raise your furnace, water heater, and electric panel in your home. Elevation prevents these appliances from being damaged by flood water.
- Avoid a Backup: Consider installing check valves, or one-way valves that allow fluid to flow through in one direction. This prevents sewage and floodwater from backing up into the drains of your home.
- Fill Sandbags: If you have access to sandbags and have the time, fill them and put them in place before the flooding occurs.
- Food & Water: Maintain a short-term food supply for you and your pets and water storage in case your drinking water becomes contaminated. Consider storing alternative fuels should you lose electricity.
#4 Understanding the alert system
Flood alerts can give you valuable time to prepare, take action, or evacuate. Because flooding can develop quickly and may affect one neighborhood differently than another, it is important to receive alerts from more than one source and understand what each type of alert means. FEMA, the National Weather Service, local emergency management, and city or county alert systems can all play a role in keeping you informed before, during, and after a flood.
Alert Definitions
- Flood Advisory: Flooding is possible or minor flooding may already be happening. Use caution and stay informed.
- Flood Watch: Conditions are favorable for flooding. Prepare now and be ready to act.
- Flood Warning: Flooding is imminent or already occurring. Take action and follow official instructions.
- Flash Flood Warning: Dangerous flooding may happen quickly or is already happening. Move to higher ground and avoid flooded roads.
- Evacuation Order: Local officials are telling people in a specific area to leave. Follow the order and use recommended evacuation routes when provided.
#5 Being ready to evacuate
- Sign Up for Alerts & Notifications: Learn how the alert system works and how to sign up.
- Evacuation Plan: Have an emergency evacuation plan in place for your family and pets – this will provide you with more options rather than being solely reliant on city plans. If you live in a flood-prone area, make this a priority.
- Evacuation Kit: Create a grab & go bag for each member of your family including your pets. If you live in a flood-prone area, add a high visibility vest to your go bag as well.
- Emergency Binder: Store copies of your important documents in a grab & go binder that you can take on your way out. If your home is flooded, you will have your information with you.
During a Flood
What you and your family do during a flood can be the difference between life and death. Always listen to your local authorities and be ready to get out.
#1 Evacuating your home
- Evacuate Immediately When told to do so - leave your home immdiately. Waiting too long can make roads impassable and reduce your ability to leave safely.
- Get Our of Harm's Way: Go to a safe destination outside the flood area - this may be a friend or family member’s home, hotel, or official emergency shelter.
- Use Official Evacuation Routes: When available, official routes have been determined to be the best way out of your area. Avoid shortcuts, low-lying roads, underpasses, and areas near rivers, creeks, washes, or drainage channels.
- Take Only Ready-to-Go Essentials: Bring people, pets, grab & go bags, and emergency binder, but do not delay leaving to gather belongings.
- Stay Informed as You Travel: Road closures, shelter locations, and evacuation instructions may change quickly.
- Return Only When Permitted: Do not return home until officials say it is safe. Flooded areas can remain dangerous even after the water starts going down.
#2 when driving
A car caught in swiftly moving water can be swept away in seconds. 12 inches of water can float a car or small SUV. 18 inches of water can carry away larger vehicles.
- Stop at Floodwater's Edge: Never drive through floodwater - turn around and choose another route.
- Stop at Barricades: Never drive around barricades - they have been placed there for safety reasons.
- Stay Off Bridges: Fast moving water can wash away bridges without warning - find another route.
- When Trapped: If you find yourself stuck in your car, call 911 so the authorities know you need help. Stay inside the main compartment for as long as you can, then move to the roof as water levels rise.
#3 when walking
If you encounter floodwater, turn around – don’t drown! The water may be deeper than it appears. It only takes 6 inches of moving water to knock you off your feet.
- Stop at Floodwater's Edge: Never walk or swim through floodwater - turn around and choose another route.
- Hidden Hazards: Sharp objects, washed-out road surfaces, electrical wires, chemicals, etc., can cause harm.
- When Trapped: If you are trapped by moving water, do not swim or wade through floodwater. Move to the highest possible point and call 911.
- Find a Safer Area: If you are forced to relocate while you're waiting for help, look for slower-moving waters. Test the ground in front of you with a stick to detect any threats below the surface.
#4 Sheltering-in-place
If you are unable to evacuate, there are some places in your home that offer more safety, depending on the layout of your home.
- Locate Your Grab & Go Bag: You can use the items you packed inside to keep you fed, hydrated, warm, and your surroundings lit if the lights go out.
- Head Upward: Get to the highest level of your home, only getting on the roof if necessary. Do not climb into a closed attic to avoid getting trapped by rising floodwater.
- When Trapped: Signal for help or call 911 as soon as you are situated in a safe place.
#5 Practicing electrical safety
If your area is not evacuated, you still need to be vigilant as things can rapidly change. Some disasters are brought on suddenly with no warning ever given. If you find your home flooding and it's too late to get out, there are a few safety protocols you can follow to make sure you stay safe.
- Caution When Entering Rooms: Do not go into any room that has water covering the electrical outlets or has cords submerged.
- Listen for Noises: If you hear buzzing, crackling, snapping, or popping, or see sparks – stay out of this area! An electrical current may be running through the water.
#6 Receiving Real-Time Flooding Reports
While FEMA's Flood Map helps you understand mapped flood zones, the U.S. Geological Survey’s WaterWatch Flood Map can help you stay aware of changing water conditions during storms.
- During Flood Event: These reports are useful during storms and heavy rain. This tool can monitor nearby rivers, creeks, or waterways during a storm, especially if your area has a history of flooding.
- Streamgage Technology: The map relies on USGS monitoring stations, so it is most useful where a nearby streamgage exists. It may not show flooding caused by poor drainage, overflowing streets, or small local waterways without gauges.
- Active Updates: USGS WaterWatch data is generally updated frequently, often hourly, making it useful for checking changing conditions during an active weather event.
After a Flood
The aftermath of a flood may reveal devastating destruction and many present dangers. Homes, businesses, and roadways may be damaged or destroyed. After an evacuation, return home only when authorities give you the green light to do so. Proceed with caution.
#1 Exterior hazards
- Look for Damage: Assess damage to power and gas lines, foundation cracks, your home's exterior, and downed or unstable trees and poles.
- Turn Off Utilities: This includes water, gas, and electricity - this can pose a huge risk of electrocution inside your home.
- Stay Out of Floodwater: It can contain dangerous debris like broken glass, metal, dead animals, sewage, gasoline, oil, and downed power lines. They can also contain unwanted guests that are very much alive like rodents, snakes, insects, and other animals. They may be inside your home as well.
#2 Fixing, Cleaning & Disinfecting
- Use PPE: Use appropriate personal protective equipment to avoid injury from possible exposure to mold and bacteria including gloves, safety glasses, rubber boots, and N95 masks.
- Look for Mold: Mold growth is very likely depending on how long you have been away from your home. Find and remove it properly.
- Open Windows and Doors: Air out and dry out your home by opening all doors and windows whenever you are present. Leave as many windows open when you are not present as security concerns allow.
- Remove Porous Items: Some items cannot be cleaned or disinfected. These include some types of flooring, paneling, drywall, insulation, mattresses, carpeting, upholstered items, stuffed animals, and other baby toys.
- Clean and Disinfect: Clean the remaining hard surfaces like floors, countertops, and appliances with hot water and soap or detergent. Mud left from floodwater can contain sewage, bacteria, and chemicals. Remove properly.
#3 Food & water hazards
- Throw Out Food & Bottled Water: Food that hasn’t been kept at a safe temperature - or that has come into contact with floodwater - must be discarded. Do not eat produce from a garden that has been flooded. When in doubt, throw it out. The same rule applies to bottled water: if the bottle was submerged in floodwater, do not drink it.
- Boil Water Before Using: Do not drink tap water unless officials have confirmed it is safe. Never assume safety after a flood or water‑system disruption. Until you receive an official “all clear,” boil all tap water before use and monitor alerts from your city or water district. Do not use unboiled tap water for washing dishes, brushing teeth, or washing or preparing food.
#4 Other Considerations
- Keep Monitoring Alerts: Emergency information may continue after the water recedes. Alerts may include road closures, boil water notices, shelter locations, re-entry instructions, utility hazards, or additional rainfall warnings.
- Avoid Driving: When possible, stay off the roads right after a flooding event.
- Avoid Flooded Areas or Standing Water: These areas can hide dangerous toxins, chemicals, sharp objects, snakes, and electrified water.
- Avoid Disaster Areas: Your presence may hamper restoration, rescue, or other emergency operations.