Water Quality Test Results
Maximum Contaminant Level Goal: The level of a contaminant in drinking water below which there is not known or expected risk to health. MCLGs allow for a margin of safety.
Maximum Contaminant Level or 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 Residual Disinfectant Level Goal or 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 contaminants.
Maximum Residual Disinfectant Level: 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.
Avg: Regulatory compliance with some MCLs is based on running annual average of monthly samples.
ppm: Milligrams per liter or parts per million - or one ounce in 7,350 gallons of water.
ppb: Micrograms per liter or parts per billion - or one ounce in 7,350,000 gallons of water.
pCi/L: Picocuries per liter (a measure of radioactivity)
90th Percentile: 90 of samples are equal to or less than the number in the chart.
EPA: Environmental Protection Agency
TCEQ: Texas Commission on Environmental Quality
Definitions: The following tables contain scientific terms and measures, some of which may require explanation.
Lead and Copper
Action Level Goal (ALG): The level of a contaminant in drinking water below which there is no known or expected risk to health. ALGs allow for a margin of safety.
Action Level (AL): The concentration of a contaminant which, if exceeded, triggers treatment or other requirements which a water system must follow.