Servicing the Cities of
Azusa, Baldwin Park, Irwindale and
West Covina in Southern California
Water Glossary

acre-foot—a volume of water that covers one acre to a depth of one foot, or 43,560 cubic feet, or 325,829 gallons.

activated carbon—adsorptive particles or granules of carbon usually obtained by heating carbon (such as wood). these particles or granules have a high capacity to selectively remove certain trace and soluble materials from water.

aquifer--a geologic formation(s) that is water bearing. A geological formation or structure that stores and/or transmits water to wells and springs. Use of the term is usually restricted to those water-bearing formations capable of yielding water in sufficient quantity to constitute a usable supply for people's uses.

chlorination – the application of chlorine to water, generally for the purpose of disinfection

contamination – the introduction into microorganisms, chemicals, toxic materials, wastes or wastewater in concentration that makes the water unfit for its next intended use.

coliform – a group of bacteria found in the intestines of warm-blooded animals (including humans) and also in plants, soil, air and water. Fecal coliforms are a specific class of bacterial, which only inhabit the intestines of warm-blooded animals. The presence of coliform bacteria is an indication that the water may contain pathogenic (disease-causing) organisms.

cross connection – a connection between a drinking (potable) water system and an unapproved water supply.

dechlorination – the deliberate removal of chlorine from water. The partial or complete reduction of residual chlorine by any chemical or physical process.

disinfection – the process designed to kill or inactivate most microorganisms in water, including essentially all pathogenic (disease-causing) bacteria. There are several ways to disinfect, with chlorine being most frequently used in water treatment.

flushing – a method used to clean water distribution lines. Hydrants are opened; water with a high velocity flows through the pipes and removes deposits from the pipes, and flows out the hydrants.

maximum contaminant level (MCL)--the designation given by the U.S.. Environmental Protection Agency (EPA) to water-quality standards promulgated under the Safe Drinking Water Act. The MCL is the greatest amount of a contaminant that can be present in drinking water without causing a risk to human health.

milligrams per liter, mg,L –a measure of concentration by weight of a substance per unit volume. For practical purposes, one milligram per liter of a substance in fresh water is equal to one part per million parts (ppm).

pH (pronounce as separate letters) –pH is an expression of the intensity of the basic or acidic condition of a liquid. Mathematically, pH is the logarithm (base 10) of the reciprocal of the hydrogen ion activity.

potable water--water that is suitable for drinking.

prechlorination the addition of chlorine at the headworks of the plant PRIOR TO other treatment processes mainly for disinfection and control of tastes, odor, and aquatic growths. Also applied to aid in coagulation and settling.

raw water – 1. Water in its natural state, prior to any treatment

                    2. usually the water entering the first treatment process of a water treatment plant.

residual chlorine – the amount of free and/or available chlorine remaining after a given contact time und specified conditions.

Safe drinking water act (SDWA) – An act passed by the US Congress in 1974. The Act establishes a cooperative program among local, state and federal agencies to ensure safe drinking water for consumers.

water tablethe upper surface of the zone of saturation of groundwater in an unconfined aquifer.

water quality--a term used to describe the chemical, physical, and biological characteristics of water, usually in respect to its suitability for a particular purpose.




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