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Guidelines for Homeowners of Flooded Properties

How to clean up flooded wells before using

Health concerns following flooding and sewage backups
Cleaning up the house after the flood.

Owners of property affected by floodwater are advised to take the following precautions in the protection of their health.

Drinking Water
Drinking water from wells or cisterns, which have been covered with floodwater, should be considered UNSAFE FOR DRINKING.

Owners are advised to use alternate supply source for their drinking water needs, or treat this water before consumption as follows:

  • Rapidly boil the water for at least 1 minute, OR
  • Small amounts of water for household use can be disinfected by adding 10 drops of household chlorine bleach to 4.5 litres/1 gallon of water, stir well, and let this mixture stand for 15 min.

Before Resuming Consumption of Well Water it MUST be Tested.
After floodwaters have receded, wells should be disinfected and the water tested for bacteriological safety. Three consecutive samples taken one week apart are required to establish drinking water stability and quality.

Food Safety
Food items, which have come in direct contact with floodwater, should not be eaten. Foods stored in leak proof containers (cans, jars, tetra-packs) may be safe provided that the container is thoroughly washed with soap and water before breaking the seal. Floodwater is usually contaminated with raw sewage.
More info on food...

Heating Hazards
Carbon Monoxide is a poisonous, odourless, colourless gas, which is always produced when any fuel is burned (propane, kerosene, wood). Burning of fuel indoors for heating or cooking purposes must only be done with good ventilation and with equipment that is approved to be used indoors. A qualified heating contractor should check a flooded furnace before it is restarted.

For further health information, please contact the Health Protection Department at 613-345-5685.

Dated: April 4, 2005

Leeds, Grenville & Lanark District Health Unit
Media Release

April 5, 2005

How to CLEAN UP FLOODED WELLS BEFORE USING

Heavy rainfall and melting snow results in flooding on many properties. If your property has been flooded, organisms carried in floodwater that could make your family sick may contaminate your well. If your well is submerged during a flood, bacteria, viruses, or parasites can enter the top of your well, or seep down along the casing, making your drinking water unsafe. Even if water from a flooded well looks clear, it cannot be regarded as safe for consumption until the well and plumbing system has been disinfected, flushed and a water test shows that it does not contain harmful bacteria. Water testing bottles and instructions are available through your local health unit office.

You should use bottled water for drinking and food preparation until your well water is safe for consumption. If you must use your well water, make sure that all well components are in good condition and that the electrical system is dry. Bring well water for drinking and food preparation to a rolling boil for at least one minute before use.

Follow the well disinfection procedure below if you are concerned that your well has been contaminated during a flood. The tools you will need are 5% (hypochlorite) household bleach, a funnel, goggles, rubber gloves, old clothes and a garden hose. For a dug well, three feet (91 cm) in diameter use 1.1 litres (1 quart) of bleach for every five feet (1.5 m) water depth. For a drilled well, six inches (15 cm) diameter, use five ounces (150 ml) of bleach for every 25 feet (7.5 m) of water depth.

  • Mix bleach with water and pour directly into well
  • Drain water heater and remove or bypass any carbon filter
  • Open all taps one at a time and let water run
  • Turn off taps when a bleach odour is noticed and let stand 12 hours
  • Drain the water system to remove all chlorinated water. Avoid draining this water into the septic tank - use a garden hose
  • Resample 48 hours later and take the sample immediately to your nearest health unit office. If satisfactory, take two more samples, each one-week apart to ensure water remains satisfactory.

For more information, please contact the Health Protection Department of the Leeds, Grenville and Lanark District Health Unit in Brockville at 613-345-5685 or Smiths Falls at 613-283-2740, or our Health Action Line at 1-800-660-5853.

Contact: Joan Mays, Supervisor, Health Protection 613-345-5685 and 1-800-660-5853


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