TABLE DEFINITIONS
SUBSTANCES EXPECTED TO BE IN DRINKING WATER
2023 WATER QUALITY REPORT page 5
TABLE DEFINITIONS
Action Level ( AL ): The concentration of a contaminant which , if exceeded , triggers treatment or other requirements which a water system must follow .
< ( numbers ): Less than the amount listed . ≥ ( numbers ): 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 .
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 .
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 .
ND ( Not Detected ): No level of the parameter was detected .
NA : Not applicable . 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 .
Raw Water : Water that has not yet been treated for consumption .
Level 1 Assessment : A study of the water system to identify possible problems and determine ( if possible ) why total coliform bacteria were found .
Level 2 Assessment : A very detailed study of the water system to identify potential problems and determine ( if possible ) why an E . Coli Maximum .
Contaminant Level ( MCL ) Violation has occurred and / or why total coliform bacteria were found on multiple occasions .
SUBSTANCES EXPECTED TO BE IN DRINKING WATER
The City of Arlington and the State of Texas both analyze your drinking water . Any regulated substances that were detected during the last year are shown in Table A on page 2 , and all are well below the established maximum contaminant levels . All water dissolves substances from the ground as it flows over and through it .
Substances that may be present in raw water include :
Microbes such as viruses and bacteria that come from septic systems , agricultural livestock operations and wildlife .
Salts and metals that can be naturally occurring or the result of urban storm water runoff , industrial or domestic wastewater discharges or farming .
Pesticides and herbicides that may come from a variety of sources such as agriculture , urban storm water runoff or residential uses .
Radioactive substances that are naturally occurring .
Organic chemical substances including synthetic and volatile organic chemicals that are byproducts of industrial processes and can also come from gas stations and urban stormwater runoff .
Contaminants may be found in drinking water that could cause taste , color , or odor problems but are not necessarily causes for health concerns . For more information , please call Laboratory Services at 817-575-8984 .