Zone 3 - the 10 year horizontal time of travel boundary

The outer border of Zone 3, the area within the 10-year time of travel boundary, determines the boundary of the WHPA. Within Zone 3, an inventory for potential contaminant sources should be conducted. High-risk operations and facilities should be identified, and steps taken to reduce contaminant loading. A primary purpose of Zone 3 is to encourage decision makers and planners to recognize the long-term source of the drinking water supplying community water systems. This allows the community to plan and site future high risk and medium risk sources of groundwater contamination outside WHPAs. Zone 3 also serves as an educational tool for industry, the general public, and others to understand the source of their drinking water and the significance of their actions upgradient of drinking water wells.

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