An Act to protect water supplies and the environment

This bill revises Massachusetts water management rules to better protect water supplies. It replaces the definition of "safe yield" (the maximum sustainable water withdrawal) to explicitly consider drought risk and natural replenishment. The Department of Environmental Protection (DEP) must now recalculate safe yield for each water basin every decade, using summer supply data and reservoir storage, and calculate it at the sub-basin level for permit decisions using U.S. Geological Survey stream flow data. These changes directly affect the DEP's water permit process and anyone seeking to withdraw water from Massachusetts sources.