Water supplied by Public Water Systems is regulated under the Federal Safe Drinking Water Act by the U.S. Environmental Protection Agency (EPA). The current enforceable copper drinking concentration level for public water supplies is 1.3 mg/L (ppm), and a discharge limit of 2 mg/L (ppm). Therefore, a water discharge with copper content between 0-2 mg/L (ppm) is safe to discharge into the environment. Please keep in mind that these are federal guidelines. State or local guidelines may be different.