Which is the recommended cleaning solution ratio for classroom use?

• A. 1 oz bleach to 1 quart water
• B. 1:30 bleach to water
• C. Enzyme cleaners
• D. Bleach needs to stand for 10 minutes to kill parvo

Answer: (A)

Disinfecting classroom surfaces effectively requires using the standard bleach-to-water dilution that is proven to inactivate canine parvovirus while remaining practical for routine cleaning. The recommended mix is one part household bleach to thirty-two parts water, which in everyday terms is one ounce of bleach in one quart of water. This concentration, when surfaces stay visibly wet for at least about ten minutes, provides reliable disinfection against parvovirus. Enzyme cleaners alone won’t reliably disinfect against parvovirus, so they aren’t the best choice for this purpose. A slightly stronger ratio like one to thirty isn’t the standard, and while the ten-minute contact time is important for effectiveness, the question here targets the correct dilution.