3. What does it mean that the maximum contaminant level goal for arsenic is 0 mcg/L in drinking water?

  • The maximum contaminant level goal (MCLG) is defined by USEPA as the level of contaminant in drinking water below which there is no known or expected risk to health and which allows a margin of safety. Because arsenic is a known human carcinogen via drinking water, the USEPA has determined that the maximum contaminant level goal is zero for arsenic in drinking water.
  • The MCLG is usually lower than the Maximum Contaminant Level (MCL). The MCL is the highest level of a contaminant that is legally allowed in drinking water.  MCLs are set as close as feasible to the MCLGs. For arsenic, the New Jersey MCL is 5 mcg/l.