What Are Floods?

Flooding is an overflow of water that can range from a few inches deep to fully submerging entire buildings. Flooding can occur when rivers and lakes cannot contain excessive rain or snow melt, rain cannot be absorbed fully into the ground, waterways overflow due to debris or ice, winds from tropical storms or hurricanes cause storm surge in coastal areas, or water containment systems (such as levees, dams, pipes) break.

Why Prepare?

Flooding is the most common hazard in Massachusetts. Some floods develop slowly, while flash floods can occur within minutes or hours after a storm or containment system break.

Flooding is a leading cause of death in many disasters. Learn how to prepare for a flood, stay safe during a flood, and protect your health when you return home after a flood. 

The National Weather Service issues flood watches and warnings to alert the public of potential severe weather. It is important to understand the difference between watch and warning so you know what to do to stay safe:

Flood Watch or Flash Flood Watch

Flooding or flash flooding in your area is possible.  Pay attention to changing weather and flood conditions, and be prepared to move to higher ground.

Flood Warning

Flooding is occurring or about to occur. Avoid low lying areas and if necessary, evacuate.

Flash Flood Warning 

A flash flood is occurring or about to occur. Seek higher ground immediately.

Before a Flood

  • Be informed by receiving alerts, warnings, and public safety information before, during, and after emergencies. Download the Massachusetts Alerts app.
  • Find out whether your property is in a flood-prone or high-risk area. Explore the Federal Emergency Management Agency’s (FEMA) flood maps.
  • Contact your local Emergency Management Director to find out if your home or workplace is downstream from a dam and learn more about your community’s risk of flooding.
  • Create and review your family emergency plan.
    • Have a plan to go to higher ground quickly if necessary.
    • If you live or work in a flood zone, hurricane evacuation zone, or an area that is prone to flooding, you should be prepared to evacuate.
  • Assemble an emergency kit.
  • Make a record of your personal property by taking photos or videos of your belongings. Store these records in a safe place.
  • Prepare your home for flooding.
  • Flood losses are not typically covered under renter and homeowner’s insurance policies. Consider purchasing flood insurance through the National Flood Insurance Plan (NFIP). Flood insurance is available in most communities whether or not your building is in a flood-prone area, but there is a 30-day waiting period before it goes into effect.

During a Flood Watch or Flash Flood Watch

  • Listen to a National Oceanic and Atmospheric Administration (NOAA) Weather Radio or to a local news station for the latest information.
  • Follow instructions given by public safety officials.
  • Be alert to changing weather conditions and be prepared to move to higher ground.
  • Consider postponing outdoor activities.
  • Secure or bring in outdoor objects (patio furniture, children's toys, trash cans, etc.) that could be swept away or damaged during flooding.
  • Consider unplugging sensitive electronic equipment before flooding occurs. However, do not touch electrical equipment if you are wet or standing in water.
  • Ensure that items stored in your basement are elevated to prevent damage. If you have a sump pump, check that it is working.
  • Consider clearing street catch basins to prevent or reduce street flooding.
  • Avoid camping or parking along streams, rivers, creeks, or other areas prone to flooding during heavy rainfall. These areas can flood quickly and with little warning.

During a Flood Warning or Flash Flood Warning

  • Move immediately to higher ground or stay on high ground.
  • Continue to monitor media for emergency information.
  • Follow instructions from public safety officials. If advised to evacuate, do so immediately.
  • If you must evacuate your home, take only essential items and bring your pets if safely possible.
  • If you must evacuate or are traveling during flooding, remember:
    • Do not walk through flowing water. Most drownings occur during flash floods. Six inches of swiftly moving water can knock you off of your feet.
    • Remember the phrase “Turn Around, Don’t Drown!” Don’t drive through flooded roads. Cars can be swept away in just two feet of moving water. If your vehicle is trapped in rapidly moving water, stay in the vehicle. If the water is rising inside the vehicle, seek refuge on the roof.
    • Do not drive around road barriers. Roads and bridges may be washed out or structurally unsound.
  • If told to shelter in place, listen to local television or radio for updates. Conditions may change quickly, so be prepared to evacuate to a shelter or a neighbor’s home if necessary.

After a Flood

  • Continue to monitor the media for emergency information.
  • Follow instructions from public safety officials.
  • If you have evacuated, return home only when authorities say it is safe to do so.
  • Call 9-1-1 to report emergencies including downed power lines and gas leaks.
  • Call 2-1-1 to obtain shelter locations and other disaster information.
  • Be a good neighbor. Check on family, friends, and neighbors, especially the elderly, those who live alone, those with medical conditions, and those who may need additional assistance.


  • Stay away from downed utility wires.  Always assume a downed power line is live. Electrocution is also a serious danger in floods as electrical currents can travel through water.
  • “Turn Around, Don’t Drown!” - Don’t drive through flooded roads.
  • Stay out of damaged buildings and away from affected areas or roads until authorities deem them safe.
  • If your power is out, report outages to your utility company and follow our power outage safety tips.
  • Look before you step. After a flood, the ground and floors can be covered with debris, including broken bottles and nails. Floors and stairs that have been covered with mud can be slippery.
  • Listen to news reports to learn if your water supply is safe to drink. Until local authorities proclaim your water supply safe, boil water for at least one minute before drinking or using for food preparation.
  • Throw away food (including canned items) that has come in contact with floodwaters. Don’t eat food from flooded gardens. Throw away any refrigerated food that was exposed to temperatures above 40 °F for more than two hours or that has an unusual odor, color, or texture. When in doubt, throw it out!

Clean Up Your Home and Check for Damage

  • Check your home for damage:
    • Never touch electrical equipment while you are wet or standing in water. Consider hiring a qualified electrician to assess damage to electrical systems.
    • Have wells checked for contamination from bacteria and chemicals before using.
    • Have damaged septic tanks or leaching systems repaired as soon as possible to reduce potential health hazards.
    • If your home or property is damaged, take photos or videos to document your damage, and contact your insurance company.
  • Avoid entering moving or standing floodwaters. Floodwater and mud may be contaminated by oil, gasoline, or raw sewage.
  • Clean and disinfect anything that that got wet. Take precautions and wear appropriate protective equipment such as gloves, safety glasses, and face masks.
    • Flooded floors and walls should be washed with a solution of two capfuls of household bleach for each gallon of water.
    • Carpeting, mattresses, and upholstered furniture should be disposed of or disinfected by a professional cleaner.
  • Consider using professional cleaning and repair services before attempting to repair flood-damaged property.
    • Flooded floors and walls should be washed with a solution of two capfuls of household bleach for each gallon of water.
    • Carpeting, mattresses, and upholstered furniture should be disposed of or disinfected by a professional cleaner.
    • Remove and replace any drywall or other paneling that has been underwater. Use a moisture meter to make sure that wooden studs and framing are dry before replacing the drywall. Mold growth in hidden places is a significant health hazard.