What buffer distance is required between non-community public groundwater drinking sources and application sites?

• A. 200 ft
• B. 50 ft
• C. 100 ft
• D. 500 ft

Answer: (C)

Protecting drinking-water sources from pesticide contamination is the goal of creating a setback between where pesticides are applied and where groundwater used for drinking comes from. For non-community groundwater drinking sources, the required distance to keep from application sites is 100 feet. This spacing provides a reliable margin for pesticides to degrade, dilute, or be intercepted before they can travel through soil and reach a well, especially in areas with shallow or more permeable soils where groundwater can be more vulnerable. It also helps guard against any potential surface runoff or localized movement that could affect the well area.

The other distances aren’t the standard protection level in this context: a smaller buffer wouldn’t offer the same level of protection against groundwater contamination, while larger distances exceed what is typically required and may be unnecessarily restrictive.