Disaster Prep FAQ

Resources for storm and flood readiness, clean-up and recovery.

What should I do to prepare for a flood?

Extensive plans and preventive measures have been taken by the State to reduce the disruption and damage caused by flooding, but the homeowner too can take action to prevent loss and environmental contamination. Some suggested examples of activities the homeowner can take before the threat of flooding occurs can be found in the Homeowner Tips to Prevent and Minimize Environmental Damage in Flood-Prone Areas fact sheet. For more flood safety guidance, see the American Red Cross Flood Safety webpage.


Who do I call to report an emergency?

Important – For suspected contamination from oil or hazardous materials contact both:
Your Local Fire Department: 9-1-1
NHDES Spill Response: (603) 271-3899; or after hours: (603) 223-4381

  • Dam Emergency: (603) 271-3406 or after hours (800) 852-3411
  • Hazardous waste materials/waste spills: (603) 271-3899; or after hours: (603) 223-4381
  • Petroleum spills: (603) 271-3899; or after hours: (603) 223-4381
  • River Flood Damage and Hazards: (603) 271-2876
  • Toxic Air Releases: (603) 271-1370
  • State’s Public Inquiry Line: 2-1-1


What should I do if the power is out?

If your power goes off for any reason, use alternative power/heating sources safely to avoid deadly accidents, including carbon monoxide (CO) poisoning. The EPA’s CO website includes information on safely using portable generators, symptoms of carbon monoxide exposure, and more.


Is my drinking water safe if I have public water?

Flooding can cause the contamination of water with fecal matter from sewage systems and septic tanks, as well as contamination from oil, gasoline and other chemicals. Do not use contaminated water to wash dishes, brush your teeth, wash and prepare food, wash hands or make baby formula.

If you are on a public water system, check “Drinking Water Advisory” to see if your system is under a boil order. If it is, please read the information in our Boil Order Advisories fact sheets to ensure your water is safe to use.


Is my drinking water safe if I have a private well?

After a flood, private drinking water wells may have been contaminated by the floodwaters. Heavy precipitation tends to mobilize bacteria and thus highlight conditions of poor well construction. NHDES urges all private well owners whose well has been flooded to boil their water for drinking and to have their well water quality tested after the floodwaters have receded.

How to make sure your drinking water is safe:


Safety tips for during and after flooding
  • Be aware of potential chemical hazards you may encounter during flood recovery. Floodwaters may have moved containers of solvents, petroleum, or other hazardous chemicals from their normal storage places. If any propane tanks (whether 20-pound tanks from a gas grill or household propane tank) are discovered, do not attempt to move them yourself. These represent a very real danger of fire or explosion and if found, police or fire departments should be contacted immediately. To report a hazardous materials/waste spill, call 271-3899; to report a petroleum spill, call (603) 271-3644; after hours call (603) 223-4381.
  • Car batteries, even those in floodwater, may still contain an electrical charge and should be removed with extreme caution by using insulated gloves. Avoid coming in contact with any acid that may have spilled from a damaged car battery.
  • Dams are at or near flood levels. If you should observe any areas of erosion or instability around a dam, report it immediately to 271-3406 or after hours at 1-800-852-3411.
  • Do not allow children to play in floodwaters, and do not allow them to play with toys that have been in floodwater until the toys have been disinfected. For disinfection, use 1/4 cup of bleach to one gallon of water.


The sewer line near my house is overflowing; what do I do?

During severe rainstorms and flooding events, underground sewer systems and sewage treatment plants can often become overloaded with rainwater or floodwaters. This excess water can lead to discharges of raw sewage onto the streets or private property by overflowing through manhole covers. Raw sewage can also back up into your home through low level toilets, sinks and floor drains. Untreated sewage contains potential high levels of disease-causing viruses and bacteria. Assume that all flood waters are contaminated and avoid direct contact as much as possible. If you notice sewer overflows, contact your sewage treatment plant or public works department immediately. More information on dealing with flood waters: Contaminated Floodwater—Do’s and Don’ts, OSHA fact sheet; Health Risks from Flood or Standing Waters, CDC web page; Maintain Good Hygiene/Hand Washing Practices after a Disaster or Emergency, CDC web page.


What can I do if my home is flooded?

If your home becomes flooded, be wary of contaminated flood water, which can cause serious threats to your health and to the structure of your house. It’s important to limit your contact with flood water; pump out flooded basements gradually; dry out the building; discard soaked items that can’t be thoroughly cleaned and dried; and service damaged septic systems as soon as possible. See below for more tips.

Some things you should do to minimize your risk:

  • Dry out the building. Contaminants in flood waters can penetrate deep into porous materials and later get into the air or water. Completely drying out a building will take time, and you may have to remove ceilings, wallboard, insulation, flooring and other materials if they were soaked. Discard wet materials that can’t be thoroughly cleaned and dried.
  • Limit your contact with flood water. Don’t even breathe mists from contaminated water. When cleaning, wear gloves, goggles, and a respirator or a dust mask.
  • Microorganisms will continue growing as long as things are wet. When fumes aren’t a problem and if electricity is available and safe, you can remove moisture by closing windows and running a dehumidifier or window air conditioner.
  • Pump out flooded basements gradually (about one-third of the water per day) to avoid structural damage. If the water is pumped completely in a short period of time, pressure from water-saturated soil on the outside could cause basement walls to collapse.
  • Service damaged septic tanks, cesspools, pits and leaching systems as soon as possible. Damaged sewage systems are health hazards.
  • More information on the Recovery After a Disaster webpage from American Red Cross.

How can I get rid of mold?

Mold is a serious problem in flooded areas. The key to controlling mold growth is by controlling moisture – and doing it quickly.

  • Dry out the building. Completely drying out a building will take time, and you may have to remove ceilings, wallboard, insulation, flooring and other materials if they were soaked. However, these materials may also contain asbestos and should be tested first if in doubt.
  • Microorganisms will continue growing as long as things are wet. When fumes aren’t a problem and if electricity is available and safe, you can remove moisture by closing windows and running a dehumidifier or window air conditioner.
  • If you see mold or if there is an earthy or musty smell, you should assume a mold problem exists. Remove water damaged materials. Wash mold off hard surfaces with detergent and water, and dry completely. A disinfectant may be used to kill mold missed by the cleaning.


What steps should I take to clean up fallen trees?

Uprooted trees, broken tree limbs, stumps, brush and leaves must be dealt with as soon as possible when they pose an immediate threat or hazard.  Tree tops, limbs, saplings, and tree cuttings that are 5 inches in diameter or less can be burned, provided that a permit is obtained from the local fire warden in the town where the burning will occur. Larger scale cleanup may require forestry and timbering permits. Please see page 2 of “Management of Collected Debris Following Severe Storm Events” concerning vegetative debris. Cleanup requires specific actions when the vegetative debris is within a wetland area or Protected Shoreland, such as Wetlands Emergency Authorizations.


What should I do with insulation, asbestos and other waste debris?

Natural disasters and emergencies can create myriad waste debris of every description, including petroleum and chemical spills, dislodged propane tanks, demolition wastes, damaged white goods, dead animals, and more. Hazardous wastes should be reported immediately to both your local fire department at 9-1-1 and the NHDES Spill Response team at (603) 271-3899 or after hours at (603) 223-4381. Read the “Management of Collected Debris Following Severe Storm Events” fact sheet for detailed guidance on various types of debris.

Cleanup after flooding often involves removing ceilings, wallboard, insulation, flooring and other materials if they were soaked. But those materials may contain asbestos-particularly from older buildings – get it tested first. Asbestos can cause many negative health effects. If your home contains asbestos and any of these materials have been damaged or will be disturbed during cleanup, talk to local public health authorities, and follow these tips:

  • Avoid activities that will generate dust, such as sweeping or vacuuming debris that may contain asbestos or lead.
  • Only homeowners and licensed Abatement Contractors are allowed to remove asbestos-containing materials.
  • Removed materials should be handled while still wet or damp, double-bagged and labeled, and transported to an approved landfill.
  • Wear gloves, a respirator, and disposable suit, which are all available at home centers.

For more information about asbestos, call 271-1373.


How do I handle household chemicals?

Returning to a flood-damaged home or building? Be alert for leaking containers and household chemicals such as caustic drain cleaners and chlorine bleach.

  • Don’t combine chemicals to avoid dangerous or violent reactions.
  • Don’t dump chemicals down storm sewers, drains or toilets.
  • Don’t burn household chemicals.
  • Keep children and pets away from leaking or spilled chemicals.
  • Mark and set aside unbroken containers until they can be properly disposed of. To prevent leakage, broken or damaged containers should be placed in a secondary container and marked and labeled for easy identification.


I’ve seen propane tanks adrift; who should I call to report?

Oil tanks and propane tanks are frequently dislodged and moved considerable distances during floods and other disasters. When found they should be examined by trained personnel before relocating. If oil tanks contain product, they should be pumped out, cleaned and removed by an oil remediation contractor, then handled through the scrap metal portion of the demolition debris waste stream. Scrap metal facilities are not permitted to accept tanks with residue and sludge.

Large propane tanks should be off-loaded and removed by the propane company that owns them or by a hazardous waste contractor. Smaller, 20-pound cylinders may be collected and staged at a central location. Once the remaining gas has been removed, the tanks de-valved and deemed empty by a propane contractor, the tanks can enter the scrap metal waste stream.


My septic system is flooded, what should I do?

Service damaged septic tanks, cesspools, pits and leaching systems as soon as possible. Damaged sewage systems are serious health hazards. If after a flood event you notice that your sinks and toilets are not draining properly, your septic system may be impaired or damaged. Have your septic tank pumped as soon as possible, and schedule a licensed septic system designer to assess your system for damage. This fact sheet on replacing a septic system provides details on the regulations.

If, however, your septic system was in good shape prior to the flood event and you are not experiencing drainage problems indoors, wait for the flood waters to recede and for your yard to dry. Your system will self-correct if it has not been damaged. More information is available on our septic systems webpage.


What permits are needed for shorefront, beachfront or wetland cleanup?

Cleanup requires specific actions when the vegetative debris is within a wetland area or protected shoreland, including beachfronts. For details, see the “Wetlands Emergency Authorizations” fact sheet.  


Guidance for municipalities and public drinking water and wastewater systems.

Safe and secure drinking water is the highest priority, and water systems are continuing to assess their vulnerabilities and taking action to maintain and improve emergency response and security. Community and non-community, non-transient water systems must notify the NHDES Drinking Water and Groundwater Bureau within 24 hours of an emergency or security breach.


Other Resources

NHDOT Road Closings
NOAA Weather & Disaster Information
Real-time Lake Level Information
EPA Information on Flooding Response