August 29, 2005 - Hurricanes or tropical storms, especially if accompanied by a tidal surge or flooding, can contaminate the public water supply. Drinking contaminated water may cause illness. Individuals cannot and should not assume that the water in the hurricane/tropical storm-affected area is safe to drink. The Mississippi Department of Health (MDH) will continually monitor and test water systems when necessary to ensure that water from public water systems is safe for consumption. Complete testing requires two clear samples and typically takes 48 to 72 hours.

In an area hit by a hurricane or tropical storm, water treatment plants may not be operating. Even if plants are operating, storm damage and flooding can contaminate water lines, especially if pressure is lost. Listen for public announcements about the safety of water supply systems.

If your well has been flooded, it needs to be tested and disinfected after the storm passes and the floodwaters recede. Questions about testing should be directed to your local county health department or the Mississippi Department of Health.

Water for Drinking and Cooking

Safe drinking water includes bottled, boiled or treated water. Your state or local health department can make specific recommendations for boiling or treating drinking water in your area. Remember these general rules concerning water for drinking and cooking:

• Do not use contaminated water to wash dishes, brush your teeth, wash or prepare food or make ice.
• If you use bottled water, know where it came from. Otherwise, water should be boiled or treated before use. Drink only bottled, boiled or treated water until your supply is tested and found safe.
• Boiling water kills harmful bacteria and parasites. Bringing water to a rolling boil for 1 minute will kill most organisms.
• Water may be treated with chlorine or iodine tablets or by mixing eight drops (1/8 teaspoon) of unscented, ordinary household chlorine bleach (5.25 percent sodium hypochlorite) per gallon of water. Mix the solution thoroughly, and let stand for about 30 minutes. However, this treatment will not kill parasitic organisms.

Containers for water should be rinsed with a bleach solution before reusing them. Use water storage tanks and other types of containers with caution. For example, fire truck storage tanks as well as previously used cans or bottles may be contaminated with microbes or chemicals. Do not rely on untested devices for decontaminating water.

Disinfecting Water Wells

It is extremely important to disinfect both the well and plumbing with chlorine bleach to ensure that all infectious agents are killed. If you have water treatment devices, remove all membranes, cartridges and filters and replace them with new membranes, cartridges or filters after the chlorination process is completed.

The amount of chlorine and the length of time you allow it to remain in your system are equally important. Common unscented laundry bleach can be used effectively as a chlorine disinfectant. Follow these steps for the recommended usage amount of chlorine bleach:

• If the water is discolored before chlorination, run the water until it is clear for up to 10 minutes.
• Turn off and then drain your hot water heater. Chlorine is not effective in water above 105 degrees.
• Remove and replace charcoal filters after the chlorination process is completed.
• To avoid adding contamination to the well during disinfection, first clean the work area around the top of the well. Remove grease and mineral deposits from accessible parts of the well head and flush the outside surfaces with 1/2 cup of laundry bleach in 5 gallons of water.
• Turn off the pump. Remove the cap or the well plug on the rubber seal. There are many types of well caps and plugs. If you have questions, you should contact a licensed well driller. If you have a submersible pump, you may also want to contact a licensed well driller for advice on disinfection procedures. Try to coat the sides of the casing as you pour. If you get chlorine on the pump or wiring, flush it thoroughly with fresh water to prevent later corrosion. Your local county health department may issue additional guidance for your area.
• Re-cap or plug the well opening and wait 24 hours.
• Turn on and, if needed, re-prime the pump. Open all the faucets on the system one by one. Allow the water to run until there is a noticeable smell of chlorine. You may also want to flush the toilets. If you have outside faucets, you may want to direct the water away from sensitive plants. If you cannot detect a chlorine odor, re-chlorinate the well.
• Turn off all the faucets and allow the chlorine to remain in the system for at least eight hours.

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