Is Your Groundwater Under the Influence of Surface Water?

Groundwater sources under direct influence of surface water must comply with the Surface Water Treatment Rule (SWTR). Groundwater sources that are not directly influenced by surface water are not subject to the rule. When is groundwater influenced by surface water, and when is it “directly” influenced? These are key questions for water suppliers that use groundwater from an aquifer that is recharged by a surface water source. This brief article clarifies “direct influence.”