This document has been prepared to allow toxicological evaluation of the unregulated contaminant p-tert-butylphenol in drinking water, as an extractant from one or more drinking water system components evaluated under NSF/ANSI/CAN 61 (2019), or as a contaminant in a drinking water treatment chemical evaluated under NSF/ANSI/CAN 60 (2019). Both non-cancer and cancer endpoints have been considered, and risk assessment methodology developed by the U.S. Environmental Protection Agency (U.S. EPA) has been used and are described in NSF/ANSI/CAN 600 (2019).