What is the action level for the 90th percentile lead level in drinking water?

The action level for the 90th percentile lead level in drinking water is established at 0.015 parts per million (ppm). This level is set by the Environmental Protection Agency (EPA) under the Lead and Copper Rule, which is designed to protect public health by minimizing lead and copper in drinking water.

The significance of the 90th percentile is that it measures the concentration of lead in drinking water samples from households, where 90% of those samples must be below this threshold. When lead levels exceed this action level, water systems are required to take specific actions to reduce lead levels and protect public health, which may include corrosion control treatment, public education, or system-wide lead service line replacement.

Understanding this figure is crucial for water operators as it directly impacts compliance and the strategies necessary to ensure safe drinking water. Monitoring and maintaining lead levels below the action level is a key responsibility for operators in ensuring the health and safety of the community served.