City of Portsmouth, Health Department, 1 Junkins Avenue, Portsmouth, NH 03801. Tel: (603) 610-7273

Health Department Home 

Food Permits 

Coffee Service 

Food Recalls 

City Home 

Cleaning After A Flood Floodwaters can contain many contaminants and hazards. Chemicals, fuels and bacteria can be mixed in with floodwater. Also objects that have moved during the flooding can present injury hazards. Try to limit your exposure to flood water and wear protection while cleaning. Gloves, goggles and masks are recommended.

If you use a private well that may have been flooded, have the water tested to make sure it has not been contaminated before using it for personal hygiene, mixing medications or baby formulas, or to prepare foods or to clean any surfaces that food may come into contact with.

Food safety:
  • Throw away food that may have come in contact with flood or stormwater. Throw away food that has an unusual odor, color, or texture.
  • Throw away perishable foods (including meat, poultry, fish, eggs and leftovers) that have been above 40 degrees Fahrenheit (F) for 2 hours or more.
  • Thawed food that contains ice crystals or is 40 degree F or below can be refrozen or cooked.
  • Throw away canned foods that are bulging, opened, or damaged.
  • Food containers with screw-caps, snap-lids, crimped caps (soda pop bottles), twist caps, flip tops, snap-open, and home canned foods should be discarded if they have come into contact with floodwater because they cannot be disinfected.
  • If cans have come in contact with floodwater or storm water, remove the labels, wash the cans, and dip them in a solution of 1 cup of bleach in 5 gallons of water. Re-label the cans with a marker.
  • While the power is out, keep the refrigerator and freezer doors closed as much as possible.
  • Add block ice or dry ice to your refrigerator if the electricity is expected to be off longer than 4 hours.
Info on flooded basements:
  • Pump out basements gradually (about one-third of the water per day) to avoid structural damage. 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.
  • Dry out the building. Contaminants in floodwaters can penetrate deep into porous materials and later get into the air or water.
Household Chemical Dangers:
Household cleaners and other chemical containers may be damaged or spilled.
  • During clean-up, do not mix liquids in the same disposal container; some ordinary household chemicals can combine to become life-threatening compounds.
  • Keep children and pets away from areas of spillage.
  • Do not dump chemicals on ground, down storm drains, or into the household plumbing.
  • Label containers of hazardous waste if the original labels are unreadable, or if the containers are placed into secondary containers.
  • Dispose of chemicals properly and follow the local waste facility guidelines.
To prevent or control mold growth, act quickly to remove and dry wet items.
  • Remove standing water.
  • Remove wet articles.
  • Remove wet building materials if they are unable to be dried and cleaned. Carpeting is very difficult to salvage.
  • Dry the affected areas. With windows closed, run a dehumidifier, or a window air conditioner. If you have fans only, when the weather is dry, open windows and circulate the air with the fans. Always be careful of electricity in wet areas.
  • Mold can be washed off of items and walls with detergent and water. Be sure to dry items/areas that have been washed, particularly in basement areas.
  • For heating or drying, avoid using equipment indoors that burns fuel, such as gasoline-powered generators, or camping equipment such as stoves, lanterns, or grills because they emit carbon monoxide, an extremely dangerous, colorless, odorless gas. Do not use indoors. Even ventilation will not protect against carbon monoxide indoors. Also have gas/oil water heaters and furnace exhausts checked to make sure they are still operational and have not been blocked by floating debris.
  • Avoid activities that will generate dust when cleaning dry areas. Many potentially toxic materials can become airborne and breathed in to become a potential health threat. It is best to clean while surfaces are wet.
  • If you see mold that covers more than 10 square feet, consider getting a professional to remove it.
Please Note: Ceiling and flooring materials, wallboard, and insulation, particularly around boilers and overhead pipes, may contain asbestos. Ensure that the materials you are removing do not contain asbestos; to be sure, have the materials tested. Asbestos is a hazardous material and must be handled and disposed of properly. The Portsmouth Recycling Center is not equipped to handle asbestos. For further information, see the NH DES contact information below.

When your home is well on its way to being dried out, take a few minutes to look around your yard to eliminate sources of standing water that could provide a mosquito-breeding environment after flooding.
  • Discard containers and other debris that has landed on the lawn.
  • Empty tires and non-draining flower pots, and drills holes in recycling containers that are stored outside.
  • Store wheelbarrows and wading pools overturned so they do not collect water.
  • Clean rain gutters and maintain pools and hot tubs.
Additional Resources