In emergency situations, when access to a safe water source is compromised and boiling is not possible, chemical disinfection serves as a reliable method to make water potable. This process neutralizes disease-causing microorganisms, such as bacteria and viruses, that may be present in the water supply. Household liquid chlorine bleach, which contains the active ingredient sodium hypochlorite, is a readily available chemical that effectively achieves this necessary disinfection. Utilizing this method requires precise measurement and adherence to established guidelines to ensure the water is safe for consumption.
Selecting the Right Bleach for Water Treatment
Selecting the correct product is essential, as not all household bleach is suitable for treating drinking water. Only regular, unscented liquid chlorine bleach containing sodium hypochlorite as the sole active ingredient should be used. Varieties labeled as “splash-less,” “color-safe,” or those containing added scents, gels, or cleaners must be avoided, as these additives can be toxic when ingested. The effectiveness of the treatment hinges on the concentration of sodium hypochlorite, which is typically found in concentrations of either 6% or 8.25%. It is necessary to check the label for this percentage, as it directly dictates the amount of bleach required in the next step. Furthermore, sodium hypochlorite degrades over time, so the bleach should be fresh, ideally stored for less than one year, to ensure its full disinfectant strength.
Calculating the Specific Dosage
The amount of bleach needed to sanitize water is dependent on the sodium hypochlorite concentration listed on the bottle. For the standard 8.25% concentration, the recommended dosage for one gallon of clear water is six drops. If using the 6% concentration, the dosage must be increased to eight drops of bleach per gallon of clear water. Measuring the small volume is most accurately done using a clean eyedropper, which ensures the precise delivery of single drops into the water. For treating larger quantities, such as five gallons of clear water, the dosage for a 6% concentration translates to approximately one-half teaspoon of bleach. This calculation establishes the minimum necessary amount to achieve effective disinfection and must be strictly followed.
Step-by-Step Sanitization Process
If the water appears cloudy or contains visible sediment, it should first be pre-filtered. Passing the water through a clean cloth, coffee filter, or paper towel removes suspended particles, which otherwise inhibit the action of the sodium hypochlorite. Once the water is visibly clear, the calculated dosage of bleach is added directly to the container. The mixture must then be thoroughly stirred or shaken for several seconds to ensure the hypochlorite solution is evenly distributed throughout the entire volume of water. Following this mixing, the container should be capped, and the water must stand for a minimum contact time of 30 minutes. This 30-minute period allows the chlorine compound to interact with and inactivate the microbial pathogens.
Addressing Water Variables and Safety Checks
The initial calculated dosage assumes the water is relatively clear and near room temperature, but adjustments are needed for challenging conditions. If the water is notably cloudy, colored, or extremely cold, the required amount of bleach must be doubled to achieve effective disinfection. Turbidity increases the organic load, consuming the chlorine before it can fully disinfect the water, while cold temperatures slow down the chemical reaction rate.
After the 30-minute waiting period, a safety check involves smelling the treated water. The water should have a faint, distinct odor of chlorine, which confirms that sufficient disinfectant remains in the water to kill the pathogens. If no chlorine odor is detectable, the original dosage must be repeated, and the water should then stand for an additional 15 minutes before consumption. If the chlorine odor is too strong, the taste can be improved by pouring the water between clean containers several times, a process called aeration, or by allowing the water to stand exposed to the air for a few hours. Treated water should be stored in clean, covered containers to prevent recontamination.