Water Quality Logo

Water Quality Charts

Understanding the Charts

Remember that substances are shown in parts per million or parts per billion. From these charts, you will see that water delivered by SAWS is of excellent quality.

Action Level (AL): The concentration of a contaminant which, if exceeded, triggers treatment or other requirements which a water system must follow.

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.

Avg (Average): Regulatory compliance with some MCLs are based on a running annual average of monthly samples.

Level 1 Assessment: A study of the water system to identify potential problems and determine (if possible) why total coliform bacteria have been found in our water system.

Level 2 Assessment: A very detailed study of the water system to identify potential problems and determine (if possible) why an E. coli MCL violation has occurred and/or why total coliform bacteria have been found in our water system on multiple occasions.

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.

MFL: million fibers per liter (a measure of asbestos)

Maximum Residual Disinfectant Level (MRDL): The highest level of disinfectant allowed in drinking water. There is convincing evidence that the 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 refl ect the benefi ts of the use of disinfectants to control microbial contaminants

mrem: Millirems per year (a measure of radiation absorbed by the body)

N/A: Not applicable

ND: Not detected

NTU: Nephelometric Turbidity Units

pCi/L: Picocuries per liter. (A measure of radioactivity in water)

ppb: Parts per billion or micograms per liter (µg/L) or one ounce in 7,350,000 gallons of water

ppm: Parts per million or milligrams per liter (mg/L) or one ounce in 7,350 gallons of water

ppq: Parts per quadrillion or picograms per liter (pg/L)

ppt: Parts per trillion or nanograms per liter (ng/L)

TT (Treatment Technique): A required process intended to reduce the level of a contaminant in drinking water

µmhos/cm: Micromhos per centimeter (a measure of conductivity)