How is compliance determined?

Lead and copper analytical results are evaluated against an action level, not an MCL. The lead action level is exceeded if the concentration of lead in more than 10% of tap water samples collected during any monitoring period is greater than 0.015 mg/L (i.e., if the 90th percentile level lead level is greater than 0.015 mg/L). The copper action level is exceeded if the concentration of copper in more than 10% of tap water samples collected during any monitoring period conducted is greater than 1.3 mg/L (i.e., if the 90th percentile copper level is greater than 1.3 mg/L). All samples that meet the proper site selection and sample collection procedures are used to determine the 90th percentile calculation, even if you collect samples from more sites than required.

The 90th percentile is calculated separately for lead and copper.

Show All Answers

1. What type systems have to take part in Lead and Copper Rule?
2. How is compliance determined?
3. How do I calculate the 90th percentile?
4. Who do I contact if I have not received my sample bottles or I need replacement bottles?
5. What do I do if I need to change a Lead and Copper sample location?
6. What is corrosion control? How will I know if my system must perform corrosion control?
7. I’ve sent in all my Lead/Copper samples. What do I do now?
8. After sampling, how long do I have to send in the sample bottles?