What do you mean when you say the action level has been exceeded for a drinking water system?
The lead action level is a measure of the effectiveness of the corrosion control treatment in water systems. The action level is not a standard for establishing a safe level of lead in a home. To check if corrosion control is working, EPA requires water systems to test for lead at the tap in certain homes, including those with lead service lines. Systems compare sample results from homes to EPA’s action level of 0.015 mg/L (15 ppb). If 10 percent of the samples from these homes have water concentrations that are greater than the action level, then the system must perform actions such as public education and lead service line replacement.