Consumer Confidence Report Water Quality Report-2017-ENG - Page 3

Arlington Water Utilities tests drinking water at over 120 sample sites all over the city each month. In 2017, the laboratory collected 7,327 samples and performed 16,829 tests monitoring 229 different analytes. This report contains data collected from Jan. 1, 2017 through Dec. 31, 2017, unless another time frame is noted. Here’s a little more about the laboratory team that performs that work. Water Utilities Laboratory by the Numbers: Combined years of lab experience Full-time staff 7 4 124 Part-time staff Master’s degrees – 2 chemistry, 1 education 9 3 TCEQ Water Operator licenses (3 Class A, 3 Class B, 1 Class C and 2 Class D) 6 Bachelor’s degrees - 5 biology, 1 geology Arlington Water Utilities Lab Staff Table B. Unregulated Substances. These substances are not currently regulated by EPA . The purpose of unregulated contaminant monitoring is to assist EPA in determining the occurrence of unregulated contaminants in drinking water and whether future regulation is warranted. Substance Chloroform Bromodichloromethane Chlorodibromomethane Bromoform Dichloroacetic Acid Bromoacetic Acid Dibromoacetic Acid Chloroacetic Acid Trichloroacetic Acid Units Avg. ppb ppb ppb ppb ppb ppb ppb ppb ppb 3.5 3.3 3.2 0.3 4.64 3.08 5.38 1.5 0.19 Min. Max. MCL 2.4 3.0 3.0 0.2 3.06 2.71 1.28 0.78 0.02 4.3 3.6 3.4 0.5 5.88 4.03 8.53 2.01 0.44 Not Regulated Not Regulated Not Regulated Not Regulated Not Regulated Not Regulated Not Regulated Not Regulated Not Regulated Action Level (AL) The concentration of a contaminant which, if exceeded, triggers treatment or other requirements which a water system must follow. < less than the amount listed. ≥ equal to or greater than the amount listed. 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. Other Substances of Interest Substance MCLG Possible Source NE NE 60 NE NE NE NE NE 300 By-product of drinking water disinfection; not regulated individually; included in Total Trihalomethanes. By-product of drinking water disinfection; not regulated individually; included in Haloacetic Acids. 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 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. Units Avg ppm ppm grains/gal. ppm 84.5 89.3 5.2 33 44 50 2.9 16 Sodium ppm 19.9 10.2 27 Magnesium ppm 3.6 2.7 4.5 Chloride Total: Alkalinity Hardness Hardness Calcium Min Max 119 150 6.1 41 ppm 15 10 22 Total Dissolved Solids ppm 132 96 169 pH units 8.2 7.7 8.6 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. NA Not applicable ND (Not Detected) No level of the parameter was detected. NE Not established NTU (Nephelometric Turbidity Units) A unit used when measuring turbidity, a measure of the cloudiness of the water. pCi/L (picocuries per Liter) A measure of radioactivity in the water. ppb (parts per billion, ug/L) A unit of measurement roughly equal to 1 drop in 100,000 gallons. ppm (parts per million, mg/L) A unit of measurement roughly equal to 1 drop in 100 gallons. TT (Treatment Technique) A required process intended to reduce the level of a contaminant in drinking water. 3