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 Storm
Recovery
Center
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. Here are some general rules concerning water for drinking and cooking. Remember:
- Boil-water orders are often issued after a hurricane. That's usually because the public water utility has lost pressure in its water-moving systems, making it possible for contaminants to enter water lines. Pay attention to local authorities on the status of your water supply.
- 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 six 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 thirty minutes. However, this treatment will not kill parasitic organisms.
- Do not use contaminated water to wash dishes, brush your teeth, wash and prepare food, or make ice. Use disinfected or bottled water to brush your teeth and to give to pets.
- Use only bottled or disinfected water for drinking and cooking until the public water supplies have been declared safe. The danger with tainted public supplies is from bacterial contamination that can cause severe diarrhea. Untreated diarrhea can be life-threatening.
- Water that you saved in bottles before the storm should be good for up to six months, if properly stored. Proper storage means leaving no air in the container and storing in the dark. When in doubt, disinfect it.
- 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.
- To prevent the spread of disease, wash your hands frequently with disinfected water and soap.
- Don't use water that has a dark color, an odor or contains floating material.
- Use water stored in the bathtub, from the pool, or from the tap to flush the toilet. Don't drink or cook with water from the pool.
- Bathing or showering with tap water is fine, but don't let it get in your ears. And if you shave with tap water, dab any cuts with antiseptic.
- Don't drink water from wells, especially in areas of sewage contamination.
- Use bottled water for cleaning contact lenses.
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.
You can avoid most health problems by disinfecting any tap water you'll use for cooking or drinking. Always use clean containers. Here's how:
Boiling:
- Strain solids from water first.
- Boil at a rolling boil for 10 minutes.
- Let cool.
- Add a pinch of salt for taste.
- Pour the water back and forth between clean containers to reduce the flat taste.
Liquid chlorine:
- Strain solids from water first.
- Use common household chlorine bleach, without lemon or any other scent.
- Follow the instructions on the label. If no instructions are available, add 16 drops of chlorine bleach for each gallon of water.
- Stir, let stand for 30 minutes.
- If water does not have a slight chlorine odor, repeat the dosage and let stand for 30 minutes.
- If the water doesn't smell like chlorine after second treatment, discard and find another source of water.
Disinfecting Wells
If you suspect that your well may be contaminated, contact your local or state health department or agriculture extension agent for specific advice. Here are some general instructions for disinfecting wells.
| To Disinfect Bored or Dug Wells |
- Use Table 1 to calculate how much bleach (liquid or granules) to use.
- To determine the exact amount to use, multiply the amount of disinfectant needed (according to the diameter of the well) by the depth of the well. For example, a well 5 feet in diameter requires 4 1/2 cups of bleach per foot of water. If the well is 30 feet deep multiply 4 1/2 by 30 to determine the total cups of bleach required (4 1/2 X 30 = 135 cups). There are sixteen cups in each gallon of liquid bleach .
- Add this total amount of disinfectant to about 10 gallons of water. Splash the mixture around the wall or lining of the well. Be certain the disinfectant solution contacts all parts of the well.
- Seal the well top.
- Open all faucets and pump water until a strong odor of bleach is noticeable at each faucet. Then stop the pump and allow the solution to remain in the well overnight.
- The next day, operate the pump by turning on all faucets, continuing until the chlorine odor disappears. Adjust the flow of water faucets or fixtures that discharge to septic systems to a low flow to avoid overloading the disposal system.
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Table 1. Bleach for a
Bored or Dug Well |
|
Diameter of well (in feet) |
Amount of 5.25% laundry
breach chlorine per foot of water |
Amount of 70% chlorine
granules per foot of water |
|
3 |
1 1/2 cups |
1 ounce |
|
4 |
3 cups |
2 ounces |
|
5 |
41/2 cups |
3 ounces |
|
6 |
6 cups |
4 ounces |
|
7 |
9 cups |
6 ounces |
|
8 |
12 cups |
8 ounces |
|
10 |
18 cups |
12 ounces |
|
Source: Illinois
Department of Public Health. Recommendations may vary from state to state. |
| To Disinfect Drilled Wells |
- Determine the amount of water in the well by multiplying the gallons per foot by the depth of the well in feet. For example, a well with a 6-inch diameter contains 1.5 gallons of water per foot. If the well is 120 feet deep, multiply 1.5 by 120 (1.5 X 120 = 180).
- For each 100 gallons of water in the well, use the amount of chlorine (liquid or granules) indicated in Table 2. Mix the total amount of liquid or granules with about 10 gallons of water.
- Pour the solution into the top of the well before the seal is installed.
- Connect a hose from a faucet on the discharge side of the pressure tank to the well casing top. Start the pump. Spray the water back into the well and wash the sides of the casing for at least 15 minutes.
- Open every faucet in the system and let the water run until the smell of chlorine can be detected. Then close all the faucets and seal the top of the well.
- Let stand for several hours, preferably overnight.
- After you have let the water stand, operate the pump by turning on all faucets continuing until all odor of chlorine disappears. Adjust the flow of water from faucets or fixtures that discharge into septic tank systems to a low flow to avoid overloading the disposal system.
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| Table 2. Bleach for a Drilled Well |
Diameter of Well
(in inches) |
Gallons
per foot of water |
| 3 |
0.37 |
| 4 |
0.65 |
| 5 |
1.0 |
| 6 |
1.5 |
| 8 |
2.6 |
| 10 |
4.1 |
| 12 |
6.0 |
Amount of Disinfectant Required
for each 100 gallons of water |
| Laundry Bleach (5.25% Chlorine) |
3 cups* |
| Hypochloride Granules (70% Chlorine) |
2 ounces** |
*1 cup = 8-ounce measuring cup
**1 ounce = 2 heaping tablespoons of granules |
Source: Illinois Department of Public Health.
Recommendations may vary from state to state. |
Potions of this document are from one of more of the following sources;
NOAA/NHC/NWS
US CDC
Illinois Dept of Public Health
Dade County, Florida Emergency Management
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Last Revised: October 27, 2006 11:27 AM. |
