Drinking Water Quality Glossary Cheat Sheet (DRAFT) by [deleted]

Action Level (AL): The concen­tration of a contam­inant which, if exceeded, triggers treatment or other requir­ements which a water system must follow.
CU: Color unit.
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.
Maximum Residual Disinf­ectant Level (MRDL): The highest level of a disinf­ectant allowed in drinking water. There is convincing
evidence that addition of 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 reflect the benefits of the use of disinf­ectant to control microbial contam­ina­tion.
NA: Not applic­able.
ND: Not detected.
NJ RUL: New Jersey Recomm­ended Upper Limit.
NTU: Nephel­ometric Turbidity Unit.
ppb Parts per billion: The equivalent of one second in 32 years.
ppm Parts per million: The equivalent of one second in 12 days.
ppt Parts per trillion: The equivalent of one second in 32,000 years.
pCi/L Picocuries per liter: The equivalent of one second in 32 million years.
Primary Standards: Federal drinking water regula­tions for substances that are health­-re­lated. Water suppliers must meet all primary drinking water standards.
Secondary Standards: Federal drinking water measur­ements for substances that do not have an impact on health. These reflect aesthetic qualities such as taste, odor and appear­ance. Secondary standards are recomm­end­ations, not mandates.
TON:Threshold Odor Number.
Treatment Technique (TT): A required process intended to reduce the level of a contam­inant in drinking

Drinking water, including bottled water, may contain at least small amounts of some contam­inants. The presence of contam­inants does not necess­arily indicate that the water poses a health risk. More inform­ation about contam­inants and potential health effects can be obtained by calling the EPA Safe Drinking Water Hotline at 800.42­6.4791.

The sources of drinking water (for both tap and bottled water) include rivers, lakes, streams, ponds, reserv­oirs, springs and wells. As water travels over the surface of the land or through the ground, it dissolves naturally occurring minerals, and, in some cases, radioa­ctive material, and can pick up substances resulting from the presence of animals or human activity. Contam­inants that may be present in source water include:
Microbial contam­inants, such as viruses and bacteria, which may come from sewage treatment plants, septic systems, agricu­ltural livestock operat­ions, and wildlife.
Inorganic contam­inants, such as salts and metals, which can be natura­lly­-oc­curring or result from urban stormwater runoff, industrial or domestic wastewater discha­rges, oil and gas produc­tion, mining or farming.
Pesticides and herbicides, which may come from a variety of sources such as agricu­lture, urban stormwater runoff, and reside­ntial uses.
Organic chemical contam­inants, including synthetic and volatile organic chemicals, which are byproducts of industrial processes and petroleum produc­tion, and can also come from gas stations, urban stormwater runoff, and septic systems.
Radioa­ctive contam­inants, which can be natura­lly­-oc­curring or be the result of oil and gas production and mining activi­ties.

To ensure the water is safe to drink, the EPA regula­tions limit the amount of specific contam­inants allowed in public water systems. FDA regula­tions establish limits for contam­inants in bottled water to protect public health.