Used to make water safe to drink during emergencies, off-grid living, or long-term storage
Calcium hypochlorite (commonly sold as “pool shock”) can be used to disinfect water for drinking when properly prepared. It’s lightweight, stores for over 10 years, and replaces the need for liquid bleach or tablets. This method is trusted by preparedness experts and aligns with emergency water treatment guidelines.
Ingredients:
- Calcium hypochlorite (granular, 65–70% available chlorine; no additives or algaecides)
- Water from a freshwater source (creek, river, well, or stored supply)
- Measuring spoons (1 heaping teaspoon, tablespoons)
- Non-metallic container (HDPE jug or glass jar with gasket lid)
- Non-metallic stirring utensil (plastic or wood)
- Optional: baking soda to improve taste after purification
How to Make It:
- Make a stock solution by dissolving 1 heaping teaspoon (about 7 grams) of calcium hypochlorite into 1 gallon of water. Stir until fully dissolved. This creates a concentrated chlorine solution for water purification.
- To disinfect 1 gallon of clear drinking water, add 2.5 tablespoons of this stock solution. Stir or shake and let it sit for 30 minutes. If there’s no faint chlorine smell, repeat the dose and wait another 30 minutes. A slight chlorine smell means the water has been properly disinfected. If there’s no smell, the chlorine may have been used up and the dose should be repeated.
- To treat a 250-gallon stock tank or water tote (non-potable or livestock use): Add the entire gallon of the stock solution to the tank. Stir thoroughly and let it sit for at least 30 minutes before use. This method helps sanitize large volumes of water and is suitable for cleaning storage tanks, treating animal water sources, or preparing non-drinking water for general use.
To reduce chlorine taste, add a small pinch of baking soda to each gallon of treated water, or let it sit uncovered for a few hours.
Warnings:
- Do not ingest dry calcium hypochlorite or the concentrated stock solution.
- Always add powder to water, never water to powder — adding water to dry calcium hypochlorite can cause a rapid, dangerous reaction or release of heat and gas. Mixing the other way is safer and controlled.
- Use in a ventilated area and wear gloves and eye protection.
- Keep out of reach of children and pets.
Storage & Shelf Life:
- Dry calcium hypochlorite: Use to make water purification solution; shelf life 10+ years when kept completely dry.
- Prepared stock solution (7 grams in 1 gallon): Use for water treatment; shelf life 24–48 hours.
- Treated water (after purification): Store in sealed, food-safe containers; shelf life up to 6 months.