In emergency situations, access to safe drinking water can be compromised. Whether it’s a hurricane, flood, or a simple water main break, knowing how to disinfect water is crucial for your health and safety. While bottled water is ideal, it’s essential to know how to purify water yourself. This guide will explain how to disinfect water using boiling and household bleach, focusing on the right amount of bleach per gallon to ensure you have safe water when you need it most.
Why Disinfect Water?
Emergencies can disrupt water sources, potentially contaminating them with harmful microorganisms. These pathogens can cause serious illnesses if consumed. Boiling and disinfection with bleach are effective methods to kill most of these disease-causing organisms, making water safe for drinking, cooking, and hygiene. However, it’s important to note that these methods don’t remove other contaminants like heavy metals or chemicals.
Boiling Water: A Reliable Method
Boiling is a straightforward way to disinfect water and is effective against bacteria, viruses, and protozoa.
- Preparation: If the water is cloudy, let it settle. Then, filter it through a clean cloth, paper towel, or coffee filter to remove sediment.
- Boiling Process: Bring the filtered water to a rolling boil and maintain it for at least one minute. If you are at an altitude above 5,000 feet (1,000 meters), boil for three minutes.
- Cooling and Storage: Allow the boiled water to cool naturally before storing it in clean, covered containers.
- Improving Taste: Boiled water can taste flat. To improve the taste, add a pinch of salt per quart or liter, or pour the water between clean containers a few times to re-introduce air.
Disinfecting Water with Household Bleach: What You Need to Know
When boiling isn’t possible, using household bleach is another effective disinfection method. It’s vital to use the correct type and amount of bleach to ensure water safety.
- Choosing the Right Bleach: Only use regular, unscented liquid chlorine bleach that is labeled for disinfection and sanitization. Check the label for sodium hypochlorite as the active ingredient, ideally at a concentration of 6% or 8.25%. Avoid scented bleaches, color-safe bleaches, or those with added cleaners as these are not safe for water disinfection.
- Pre-treatment: If the water is cloudy, let it settle and filter it as described for boiling.
- Bleach Dosage: The amount of bleach needed depends on the concentration of sodium hypochlorite in the bleach and the volume of water. Use a clean dropper to measure accurately. Refer to the table below for guidance:
| Volume of Water | Amount of 6% Bleach to Add* | Amount of 8.25% Bleach to Add* |
|---|---|---|
| 1 quart/liter | 2 drops | 2 drops |
| 1 gallon | 8 drops | 6 drops |
| 2 gallons | 16 drops (1/4 tsp) | 12 drops (1/8 teaspoon) |
| 4 gallons | 1/3 teaspoon | 1/4 teaspoon |
| 8 gallons | 2/3 teaspoon | 1/2 teaspoon |
*Bleach may contain 6 or 8.25% sodium hypochlorite.
Important Steps for Bleach Disinfection:
- Measure and Add Bleach: Using the table above, add the correct amount of bleach to the water. If the water is cloudy, colored, or very cold, double the bleach dosage.
- Stir and Wait: Stir the water thoroughly and let it stand for at least 30 minutes.
- Check for Chlorine Odor: After 30 minutes, the water should have a slight chlorine odor. If you don’t smell chlorine, repeat the bleach dosage and wait another 15 minutes before using the water.
- Reduce Chlorine Taste (Optional): If the chlorine taste is too strong, pour the water between clean containers and let it stand for a few hours to dissipate some of the chlorine.
Additional Emergency Water Sources and Considerations
- Emergency Water Storage: Prepare for emergencies by storing bottled water or properly treated and stored water. FEMA provides guidelines on emergency water supply planning.
- Alternative Water Sources: In emergencies, consider other water sources like melting ice cubes, draining your hot water tank, or using water from rivers or lakes. Flowing water is generally better than stagnant water, but always avoid water with floating debris, dark color, or questionable odors. Regardless of the source, always disinfect the water using boiling or bleach methods described above.
- Well Water After Floods: If your well has been flooded, disinfect and test the well water after the flood recedes. Contact your local health department for guidance.
- Filtering Cloudy Water: Disinfection is less effective in cloudy or colored water. Always try to settle and filter cloudy water before disinfecting.
Other Disinfection Alternatives
If bleach is unavailable, consider these alternative disinfection methods:
- Granular Calcium Hypochlorite (HTH): This is a strong chlorine compound. Mix one heaping teaspoon (approximately ¼ ounce) of HTH with two gallons of water to create a chlorine solution (around 500 mg/L). Then, add one part of this solution to 100 parts of water you want to disinfect. Handle HTH with caution and follow label instructions.
- Iodine: Add five drops of 2% tincture of iodine to each quart or liter of water. For cloudy or colored water, use 10 drops. Let it stand for 30 minutes.
- Water Disinfection Tablets: Tablets containing chlorine, iodine, or chlorine dioxide are available online and in stores. Follow product-specific instructions for dosage.
Conclusion
Knowing how to disinfect water is a critical skill for emergency preparedness. Whether you choose boiling or bleach disinfection, understanding the correct methods and amounts, especially how much bleach per gallon of water, will ensure you and your family have access to safe drinking water when it matters most. Stay informed, prepare in advance, and prioritize safe water in any emergency situation.
More Information
For further details on emergency water disinfection and preparedness, consult resources from the EPA and FEMA.
