Lead and Copper Rule (LCR)
A United States Environmental Protection Agency regulation dating back to 1991, LCR requires water systems to monitor drinking water that comes through faucets in homes and buildings. If lead concentrations exceed 15 parts per billion (ppb) or copper concentrations exceed 1.3 parts per million (ppm) in more than 10% of homes and businesses sampled in a regional plumbing system, the system must take actions to control corrosion and leaching. If the action level for lead is exceeded, the system must also inform the public about steps they should take to protect their health, including the possible replacement of plumbing system piping.