Under the authority of the Safe Drinking Water Act, the Environmental Protection Agency (EPA) has established the Lead and Copper Rule (LCR) (exits to US EPA website), which sets special health-based drinking water standards for lead and copper called Action Levels. Tucson Water must ensure that the Action Levels for these metals are not exceeded in more than 10 percent of the homes sampled. The value that is used to determine compliance with the Action Levels is called the 90th percentile.
Tucson Water's Water Quality Management Division is in the process of monitoring and reporting for lead and copper in order to comply with the LCR (2.5 Mb pdf file). Over many years, lead service lines in our distribution system have been replaced to reduce the risks to exposure to lead in the drinking water. High levels of lead and copper are not present in the groundwater and Colorado River water that serve as our drinking water sources. Most lead and copper in our system comes from lead-containing solder in older plumbing or from faucets or other water fixtures in homes and businesses. Our Lead and Copper in Drinking Water Fact Sheet (52 Kb pdf file) contains additional information about lead sources, risks, and recommended steps to reduce exposure.
The LCR requires that the lead and copper samples be collected from household taps used for drinking water. In June 2008, Tucson Water collected samples from the Thunderhead Public Water System (#10-179). Samples were taken from the main water system July 2008.
Analysis and reporting for the Thunderhead Water System is complete and the results were recently mailed to the participating customers. We are pleased to report that the lead and copper concentrations measured from the household taps, as well as the 90th percentile values calculated for this water system, were below the lead and copper Action Levels of 15 parts per billion and 1.3 parts per million respectively. The lead and copper samples for the main system are currently being analyzed and the results will be mailed to the participating customers in August.
We would also like to take this opportunity to thank our customers who participated in our Lead and Copper Tap Water Monitoring Program and hope we have your continued support for future monitoring events. Your participation is crucial for complying with the LCR.
Links to additional information mentioned above are provided below.