If the water is clear, how much bleach should be added to 5 gallons of water to disinfect it?

• A. 1/4 tsp
• B. 1/2 tsp
• C. 1 tsp
• D. 2 tsp

Answer: (B)

Disinfecting drinking water with chlorine relies on adding enough chlorine to leave a small residual after a set contact time. When the water is clear, you don’t need a large dose, because there are fewer substances consuming the chlorine. For five gallons of clear water, about half a teaspoon of plain household bleach (5–6% sodium hypochlorite) is enough to achieve proper disinfection after about 30 minutes; stir well and let it stand before using. This amount strikes a balance between effectively killing microorganisms and avoiding a strong chlorine taste. A smaller amount would not reliably disinfect, while a larger amount could leave the water tasting and smelling strongly of chlorine.