Copper is found in some natural waters, particularly in areas where copper has been mined. Excessive amounts of copper can occur in corrosive water that passes through unprotected copper pipes. Copper in small amounts is not considered detrimental to health, but will impart an undesirable taste to the drinking water. For this reason, the limit for copper is 1.0 mg/l.(1.3 mg/l by the copper/lead rule)  Naturally occurring copper is rarely found in Pennsylvania at such high levels as to require treatment. Copper can be removed by conventional treatment consisting of coagulation/flocculation, sedimentation, and filtration, or by lime soda softening or reverse osmosis.