TOC

2 0 2 0 W A T E R Q U A L I T Y R E P O R T 7 WATER TREATMENT DEFINITIONS Action Level (AL): The concentration of a contaminant that, if exceeded, triggers treatment or other requirements that a water system must follow. Locational Running Annual Average (LRAA): The average of sample analytical results for samples taken at a particular monitoring location during the previous four calendar quarters under the Stage 2 Disinfectants and Disinfection Byproducts Rule. Maximum Contaminant Level (MCL): The highest level of a contaminant that is allowed in drinking water. MCLs are set as close to the MCLGs as feasible using the best available treatment technology. Maximum Contaminant Level Goal (MCLG): The level of a contaminant in drinking water below which there is no known or expected risk to health. MCLGs allow for a margin of safety. Maximum Residual Disinfectant Level (MRDL): The highest level of a disinfectant allowed in drinking water. There is convincing evidence that addition of a disinfectant is necessary for control of microbial contaminants. Maximum Residual Disinfectant Level Goal (MRDLG): The level of a drinking water disinfectant below which there is no known or expected risk to health. MRDLGs do not reflect the benefits of the use of disinfectants to control microbial contamination. Nephelometric Turbidity Unit (NTU): Nephelometric turbidity unit is a measure of the clarity of water. Turbidity in excess of 5 NTU is just noticeable to the average person. Not-Applicable (N/A): Information not applicable/ not required for that particular water system or for that particular rule. Non-Detects (ND): Laboratory analysis indicates that the contaminant is not present at the level of detection set for the particular methodology used. Parts per billion (ppb) or Micrograms per liter (ug/L): One part per billion corresponds to one minute in 2,000 years or a single penny in $10,000,000. Parts per million (ppm) or Milligrams per liter (mg/L): One part per million corresponds to one minute in two years or a single penny in $10,000. Parts per trillion (ppt) or Nanograms per liter (nanograms/L): One part per trillion corresponds to one minute in 2,000,000 years or a single penny in $10,000,000,000. Picocuries per liter (pCi/L): Picocuries per liter is a measure of the radioactivity in water. Removal Ratio: A ratio between the percentage of a substance actually removed to the percentage of the substance required to be removed. Treatment Technique (TT): A required process intended to reduce the level of a contaminant in drinking water. LEAD IN HOME PLUMBING If present, elevated levels of lead can cause serious health problems, especially for pregnant women and young children. Lead in drinking water is primarily from materials and components associated with service lines and home plumbing. The Town of Cary is responsible for providing high-quality drinking water but cannot control the variety of materials used in plumbing components. When your water has been sitting for several hours, you can minimize the potential for lead exposure by flushing your tap for 30 seconds to two minutes before using water for drinking or cooking. If you are concerned about lead in your water, you may wish to have your water tested. Information on lead in drinking water, testing methods and steps you can take to minimize exposure is available from the Safe Drinking Water Hotline or at www.epa.gov/safewater/lead. In 2018, the tap water from 60 specific homes that meet regulatory requirements were tested for lead. One hundred percent showed lead levels less than the analytical detection limit of three parts per billion. For more information, visit www.townofcary.org/lead. To learn more about lead in home plumbing watch the video from American Water Works Association: Together, Let's Get the Lead Out, https://bit.ly/2VxA4Nm

• Cover