How many drops of bleach are recommended for purifying one gallon of water?

To purify one gallon of water using bleach, it is generally recommended to use 8 drops of regular, unscented liquid bleach (which contains 5.25% to 6.0% sodium hypochlorite). This concentration is effective in killing bacteria and viruses that could be present in the water, making it safe for drinking purposes.

When using bleach for water purification, it's important to allow the treated water to sit for at least 30 minutes after adding the bleach before using it. This waiting period helps ensure that the bleach has enough time to kill pathogens effectively.

The recommendation of 8 drops strikes a balance between being sufficient to disinfect the water while also not adding so much bleach that it creates an unpleasant taste or poses health risks if ingested in excess. This guideline is part of standard public health recommendations for emergency water treatment, making it an important piece of knowledge for anyone needing to ensure water safety in situations where water may be contaminated.