Water security is fundamental to emergency preparedness, as a person can survive only a few days without a supply of safe drinking water. Storing an adequate amount for long periods requires a method to prevent the growth of harmful microorganisms. Household liquid bleach, specifically its active ingredient sodium hypochlorite, is an effective chemical disinfectant for treating water intended for long-term storage. This method ensures the water remains potable by inhibiting bacterial and algal growth over time.
Identifying Safe Disinfectant Bleach
The type of bleach used for water disinfection must be selected with care to ensure safety for consumption. Only regular, unscented liquid household bleach is appropriate for treating drinking water. The label should be checked to confirm that the sole active ingredient is sodium hypochlorite, typically listed within a concentration range of 5.25% to 8.25%.
Avoid using any bleach that contains perfumes, dyes, color-safe additives, or thickeners like gels, as these substances are not safe for human ingestion. Many modern bleach formulas include surfactants or other chemicals that can be toxic when concentrated. Since liquid bleach naturally degrades over time, it is important to use a bottle that is relatively fresh, ideally less than one year old, to ensure the sodium hypochlorite concentration remains potent enough for effective disinfection.
Precise Dosage for Water Storage
The exact amount of bleach necessary depends on the concentration of the sodium hypochlorite in the product and the volume of water being treated. For most common household bleach with a concentration of 5.25% to 6%, the standard ratio for clear water is approximately 8 drops per one gallon of water, or about one-quarter teaspoon. If the bleach concentration is higher, such as 8.25%, the dosage can be slightly reduced to about 6 drops per gallon of water.
A common measurement for larger storage containers is one teaspoon of 5.25% to 6% bleach for every five gallons of water. If the water being treated is cloudy, discolored, or very cold, the recommended dosage should be doubled to account for organic matter that consumes the chlorine. This ensures sufficient free chlorine remains to kill pathogens and maintain a residual disinfectant level for storage.
After adding the measured bleach, the container must be sealed and shaken thoroughly to mix the disinfectant throughout the water volume. The treated water then requires a contact time of at least 30 minutes before it is considered disinfected and ready for long-term storage.
The effectiveness of the disinfection process is confirmed by a simple sensory check: the water should have a faint, distinct chlorine odor. If no chlorine smell is detectable after the initial 30 minutes, the dosing procedure should be repeated with the same amount of bleach, and the water should be allowed to stand for an additional 15 minutes. This slight chlorine odor confirms that a sanitizing residual level of chlorine is present, which is necessary to prevent microbial growth during storage.
Container Preparation and Long-Term Storage
The vessel used for water storage must be clean, durable, and made of food-grade material, such as specific plastics or glass. Containers originally used for milk or fruit juice should be avoided because their porous nature makes thorough cleaning and sanitation difficult. Before filling, the containers should be washed with soap and hot water, then sanitized with a strong bleach solution, typically one teaspoon of unscented bleach mixed with one quart of water.
This sanitizing solution should coat the entire interior surface for at least 30 minutes before being poured out and the container thoroughly rinsed with clean water. After the water is treated with the appropriate dosage of bleach and sealed tightly, the containers should be labeled with the date of treatment to track their shelf life. Stored water should be kept in a cool, dark location away from direct sunlight, which can degrade the plastic and the chlorine residual. The water supply should be rotated and replaced with fresh, treated water every six to twelve months to ensure quality and safety.