Preparing a long-term water supply, such as 55 gallons, is essential for emergency planning. Disinfection through chlorination is a reliable method for making water safe for consumption and extending its shelf life. This process uses readily available household liquid bleach to kill disease-causing microorganisms. Understanding the correct type of bleach, the precise dosage, and the proper procedure is necessary to ensure the water remains potable for an extended period.
Selecting the Right Bleach Product
Choosing the correct bleach is the first step in successful water purification. The product must contain only sodium hypochlorite as its active ingredient, which acts as the disinfectant. Use plain, regular household bleach that is completely unscented and free of additives.
Bleaches with scents, colors, or “splash-less” formulations contain chemicals that are unsafe for human consumption. The concentration of the sodium hypochlorite must be verified, as this concentration directly affects the required dosage. Most common household bleaches specify a concentration ranging from 5.25% to 8.25% on the label.
A higher concentration means less product is needed to achieve the required level of free chlorine in the water. Using a bleach with an unknown or incorrect concentration will result in either ineffective purification or an unpalatably high concentration of chlorine. Confirm the percentage of sodium hypochlorite before calculating the necessary amount for your 55-gallon drum.
Determining the Exact Dosage for 55 Gallons
The precise amount of bleach needed depends entirely on the sodium hypochlorite concentration of the product. The goal is to introduce a small, safe level of chlorine that is effective against pathogens. For clean, clear water, the standard recommendation is to use approximately 5 milliliters of bleach per 5 gallons of water if the concentration is between 5% and 9%.
To treat a full 55-gallon container, this translates to about 5.5 teaspoons of bleach if the concentration is 5.25% to 6%. If the bleach is a higher concentration, such as 8.25%, the required amount is slightly less, falling around 4.5 teaspoons. If the source water is cloudy, colored, or from an unverified source, this dosage should be doubled to ensure adequate disinfection.
Use a clean measuring spoon or calibrated dropper to ensure accurate measurement. These measurements are for clear water that has no visible sediment, as cloudy water requires filtration before chemical treatment. This exact measurement is necessary to create a free chlorine residual that kills microorganisms without making the water harmful or undrinkable.
Step-by-Step Purification Process
Once the precise dosage has been measured, pour the bleach directly into the 55-gallon container of water. Ensure the disinfectant is fully distributed throughout the entire volume of water by thoroughly mixing it. This can be done by securely sealing the container and rolling it on its side, or by using a clean, long utensil to stir the water vigorously.
After mixing, the water must be left undisturbed for a contact time of at least 30 minutes. This waiting period allows the chlorine to react with and neutralize any bacteria, viruses, and other pathogens. Without this necessary contact time, the disinfection process cannot be considered complete or effective.
The final verification step is to check the water for a faint chlorine odor. A slight smell indicates successful chlorination and that a safe, residual amount of chlorine remains to prevent recontamination. If no chlorine odor is detectable after the initial 30 minutes, repeat the original dosage and allow the water to stand for an additional 15 minutes before retesting.
Safe Long-Term Water Storage
Following successful purification, the water must be stored correctly to maintain its potability. The water should be kept in food-grade containers, which are designed to store consumables and prevent chemical leaching. Opaque containers are preferable because they block light, which inhibits the growth of algae and other microorganisms over time.
The container should be tightly sealed to prevent outside contamination and evaporation, then clearly labeled with the date of purification. The optimal storage location is a cool, dark place away from direct sunlight and heat sources. Store the container away from petroleum products, pesticides, or other chemicals, as plastic is slightly permeable and can absorb chemical vapors.
While properly disinfected water can last a long time, it is recommended to rotate the stored water supply every six months to a year. This ensures the water remains fresh and that the residual chlorine level has not dropped to an ineffective concentration. The older water can be used for non-drinking purposes before the container is refilled and treated again.