Which practice helps prevent contamination of the water supply during pesticide mixing?

• A. Use a backflow preventer.
• B. Mix near a water source to monitor concentrations.
• C. Use the largest possible container to reduce spill risk.
• D. Do not wear PPE to avoid interfering with handling.

Answer: (D)

Backflow prevention is essential because it blocks the chance that pesticide-contaminated water could be drawn back into the drinking water system if pressures change during mixing. A backflow preventer creates a physical barrier, so pesticides or rinsate can’t siphon into the supply even when lines are unsettled. PPE protects you, not the water system, so not wearing it doesn’t address the contamination risk. Mixing near a water source or choosing a very large container doesn’t prevent backflow and may actually raise spill risks. The safer, more effective practice is to use a backflow preventer to keep the water supply clean.