On June 7, 1991 the US EPA published the Lead and Copper Rule which requires water utilities to conduct tap water monitoring for lead and copper at the consumer tap, optimize corrosion control treatment, and if need be, initiate public education concerning the dangers of lead poisoning and begin a program for lead service line replacement. In 1992, Providence Water conducted its initial tap water monitoring. One hundred single family homes scattered throughout our distribution system were selected to participate. Since lead and copper contamination occurs in drinking water primarily due to the corrosion of household pipes and solder, utilities are required to collect samples of tap water from high-risk locations (ie homes that have lead solder installed after 1982, homes with lead pipes, and homes with lead service lines). If more than ten percent of these high-risk locations are shown to contain lead or copper in excess of the EPA established "Action Level", then the utility is deemed to be in violation of the Rule. Infants and young children are typically more vulnerable to lead in drinking water than the rest of the general population.
It is possible that lead levels at your home may be higher than at other homes in the community as a result of materials used in your home's plumbing. If you are concerned about elevated lead levels in your home's water, you may wish to have your water tested and/or flush your tap for 3 to 5 minutes before using tap water for drinking and cooking whenever a faucet has not been used for several hours. Additional information is available from the EPA Safe Drinking Water Hotline (800-426-4791). In addition to lead and copper tap water monitoring, each utility is also required to perform field water quality parameter (WQP) monitoring. Twenty-five WQP locations are examined quarterly for pH, temperature, total alkalinity, and calcium. The results of this testing provide the basis for determining compliance with RI Department of Health established violation thresholds for corrosion control treatment optimization.
As a large system, Providence Water was also required to conduct a corrosion control study to determine the most effective treatment practice for controlling corrosion. The results of this study indicated that pH/alkalinity adjustment is an effective corrosion control technique. Lime is added to increase pH and alkalinity in water at the consumer's tap, which inhibits lead from leaching out of pipes, solder, and fixtures.