How much bleach is needed to purify a 55 gallon drum of water?

To purify a 55-gallon drum of water using bleach, you typically need about 1/4 cup (approximately 60 milliliters) of unscented liquid household bleach (5-6% sodium hypochlorite). Mix the bleach thoroughly in the water and let it sit for at least 30 minutes before use. Ensure the water has a slight chlorine odor; if not, repeat the process. Always check local guidelines for specific recommendations and safety precautions.