Certainly if sourced from a pond or stream you should treat the water to eliminate organic contamination.
Water storage treatment bleach.
Use regular household bleach with the only active ingredient sodium hypochlorite.
But they may be a consideration in the storage or treatment option you choose.
The water treatment we and many other companies carry would purify the stored water up to 5 years so you don t need to worry about changing it out or over contaminating the water with bleach.
Use the table below as a guide to decide the amount of bleach you should add to the water for example 8 drops of 6 bleach or 6 drops of 8 25 bleach to each gallon of water.
This article provides simple directions for routine non emergency cleaning and disinfection of water storage tanks using household chlorine bleach.
Add 1 4 teaspoon 16 drops of bleach per gallon of water if the water is cloudy and 1 8 teaspoon 8 drops if the water is clear.
Double the amount of bleach if the water is cloudy colored or very cold.
Centers for disease control and prevention cdc provide online resources for cleaning disinfecting and maintaining cisterns and other rain catchment systems.
Emergency water storage.
For many years regular bleach contained a concentration of 5 25 sodium hypochlorite.
Stir and let stand for 30 minutes.
One option is sodium hypochlorite bleach but has been manufactured so that there are no impurities in it and as a result it is the only bleach product.
Another way to purify water is to use a small amount of regular liquid bleach.