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Water Quality Terms

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

BDL - Below Detection Level.

LRAA (Locational Running Annual Average) - the average of sample analytical results for samples taken at a particular monitoring location during the previous four calendar quarters.

MCL (Maximum Contaminant Level) - 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.

MCLG (Maximum Contaminant Level Goal) - The level of a contaminant in drinking water below which there is no known or expected risk to human health. MCLGs allow for a margin of safety.

MRDL (Maximum Residual Disinfectant Level) - The highest level of the disinfectant allowed in drinking water. There is convincing evidence that the addition of disinfectant is necessary for control of microbial contaminants.

N/A - Not Applicable.

ND - Non-Detect.

NTU (Nephelometric Turbidity Units) - Unit to measure turbidity.

org/10L - Organisms per 10 liters.

ppm - Parts per million.

ppb - Parts per billion.

pCi/L - Picocuries per liter, used to measure radioactivity.

SMCL (Secondary Maximum Contaminant Limits) - Non-mandatory guidelines established by the EPA to assist utilities in managing drinking water for aesthetic considerations, such as taste, odor and color. These contaminants are not considered to present a risk to human health at the SMCL.

TOC - Total organic carbon.

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

Turbidity - The measure of the cloudiness of water. Citizens monitors turbidity as it is a good indicator of the effectiveness of the filtration system.