What is the recommended ratio of household bleach to water for decontaminating surfaces?

• A. 1:100
• B. 10:1
• C. 1:10
• D. 1:1

Answer: (C)

Disinfection with bleach hinges on using the right concentration so the solution can effectively inactivate germs without being overly harsh on surfaces. For surface decontamination, a practical and commonly recommended mixture is one part household bleach to ten parts water. This dilution provides enough active chlorine to kill many pathogens on nonporous surfaces while remaining safer for the material and for you to handle. Diluting less (more bleach) increases corrosiveness and fumes, and diluting more (less bleach) may not disinfect effectively. After applying, keep the surface visibly wet for several minutes to ensure contact time, then Dry or rinse as appropriate for the surface and use. Always use proper PPE, work in a ventilated area, and prepare a fresh solution as needed.