Glossary & Lingo

activated carbon

Adsorptive carbon media that have a high capacity to remove certain dissolved trace  pollutants from water (ie, organics that cause taste and odour issues). 


When two or more things stick together. Water is able to stick to many surfaces due to the creation of weak surface bonds. 


The physical process of removing dissolved gases and particles that adhere to the surfaces of, or in the pores of, an adsorbent material. Adsorption occurs without chemical reaction. (Note: this is a different process to absorption which is not used in water treatment.)


The appearance of water (ie, having no discernible taste, odour, lack of clarity, water causing staining, etc). It impacts consumer confidence and acceptance of the water supply.


The water below ground and held in saturated layers of sand and rock. It acts as a water source for wells.

average daily consumption

The total demand for water during a period of time divided by the number of days in that time period. Also called the average daily demand.

AWWA – American Water Works Association

The American Water Works Association is a nonprofit, scientific and educational society dedicated to providing total water solutions to assure the effective management of water. 


Microscopic living organisms that usually consist of a single cell. Most bacteria use organic matter for their food and produce waste products as a result of their life processes.


Related to the study of bacteria.


A positively charged ion in an electrolyte solution, attracted to the cathode under the influence of a difference in electrical potential. Sodium ion (Na+) is a cation.


Compounds formed by the reaction of hypochlorous acid (HOCL or aqueous chlorine) and ammonia. It is a form of secondary disinfection. 


The application of chlorine (Chlorine Gas, Liquid Sodium Hypochlorite, Solid Calcium Hypochlorite) to water for the purpose of disinfection and oxidation.


A metering device that is used to add chlorine to water.


Any process or combination of processes of which the main purpose is to reduce the concentration of suspended matter in a liquid.


Also called settling basins and sedimentation basins. A large tank or basin in which water is held for a period of time during which the heavier suspended solids settle to the bottom by gravity. 


A group of bacteria found in humans, plants, soil, air, and water. Not all of them are pathogenic, but are used as indicator organisms for testing water quality.

Combined Chlorine

 Chlorine combined with an amine (ammonia or nitrogen) or other organic compounds to form combined chlorine compounds.


The introduction into water of pathogenic micro-organisms, chemicals, toxic substances, wastes, or wastewater in a concentration that makes the water unfit for public consumption.

conventional filtration

A centralized water treatment system, also known as conventional treatment, is a combined process of coagulation, flocculation, sedimentation (or clarification), filtration, and disinfection. It treats water in a central location and then distributes the treated water via dedicated distribution networks.

corporation stop

A type of shut off valve that is located at a street water main, is buried and non- accessible.


Chemical action which causes the gradual decomposition or destruction of a material, often an electrochemical reaction. Corrosion can be chemical, biological, or physical. Corrosion starts at the surface of a material and moves inward.


A connection between a drinking water system and a non-potable supply. It may lead to contamination of the water supply. For example, if a pump is moving non-potable water and the drinking water system is used to supply water for the pump seal, a cross-connection or mixing between the two water systems can occur.


A waterborne intestinal parasite that causes a disease called cryptosporidiosis in infected humans. Symptoms of the disease include diarrhea, cramps, and weight loss. Cryptosporidium contamination is found in most surface waters and some groundwaters. Commonly referred to as "crypto." Water treatment consisting of a 3-log reduction for Crypto and Giardia is required. 

direct filtration

A method of treating water that consists of the addition of coagulant chemicals, flash mixing, coagulation, flocculation, and filtration. The sedimentation process is omitted.


The process which kills or inactivates most microorganisms in water, including all pathogenic (disease-causing) bacteria, parasites, and viruses. There are several methods used to disinfect, with chlorination being the most frequently seen in water treatment.

distribution system

The equipment involved with the delivery of treated water from the treatment facility to the water system user. Maintaining pressure and a chlorine residual is essential to ensuring drinking water safety. 

Escherichia coli

E. coli is the predominant coliform found in warm-blooded animals’ feces. It is the most specific indicator of fecal pollution and the possible presence of pathogenic microorganisms. In drinking water, 0 occurrence of E. coli in a 100mL sample is the accepted standard. 

Fecal Coliforms

A group of bacteria, a subgroup of total coliforms that are often present in the feces of warm-blooded animals. 

filter media

Materials, such as sand, activated carbon, ion exchange, green sand, and membranes, which filter water as it passes through the filter media. 

finished water

Water that has been treated and disinfected. It is microbially and chemically safe to consume.

fire flow

Water used for fire protection.


Clumps of bacteria and particulate impurities that have come together and formed a cluster. Found in flocculation tanks and settling or sedimentation basins.


The gathering together of fine particles after coagulation to form larger particles by a process of hydraulic and mechanical mixing.

flush water main

A maintenance procedure whereby water is flushed down water mains at a high flow (velocity) rate to clean out debris and contaminants that have built up.

free chlorine

Chlorine that has combined with water to form hypochlorous acid (HOCl) and hypochlorite Ion (OCL). Free chlorine is chlorine that is available for disinfection.

free chlorine residual

That portion of the total available residual chlorine composed of hypochlorous acid (HOCl), and/or hypochlorite ion (OCl-) remaining in water after chlorination. This does not include chlorine that has combined with ammonia, nitrogen, or other compounds. To keep water safety, a chlorine residual of 0.2mg/L should be maintained in the distribution system. 


GARP stands for 'Ground water at risk of containing pathogens' and is defined as a ground water source that is at higher risk to be contaminated from any sources of human disease-causing microorganisms (pathogens); including various types of bacteria, viruses and protozoa.

gate valve

A type of valve that uses a flow control element shaped like a sliding gate to block flow, often used as isolation valves.


A waterborne intestinal parasite that causes a disease called giardiasis (GEE-are-DIE-uh-sis) in infected humans. Symptoms of the disease include diarrhea, cramps, and weight loss. Giardia contamination is found in most surface waters and some ground waters.


The supply of fresh water found beneath the Earth's surface (usually in aquifers) that is often used for supplying wells and is a source of springs. Groundwater is not infinite, it is limited in supply. 


Stands for Ground Water Under the Direct Influence of surface water.

hardness, water

A characteristic of water caused mainly by calcium and magnesium (such as bicarbonate, carbonate, sulfate, chloride, and nitrate). Excessive hardness in water is undesirable as it causes the formation of soap curds, increased use of soap, deposition of scale in boilers, damage in some industrial processes, and can also create objectionable flavours in drinking water.


An observed biological (e.g., pathogens), chemical (e.g., dissolved metals, nutrients) or physical agent (e.g., turbidity, debris) that could harm your water users or water system.

indicator bacteria

As there are multiple forms of pathogenic microorganisms present in water that can cause illness, an indicator bacteria is required to be tested for by governmental guidelines. The indicator bacteria, E Coli and Fecal Coliform, must be present at a rate of 0 occurrence in a 100mL sample after treatment. 


An electrically charged atom, radical (such as SO42-), or molecule formed by the loss or gain of one or more electrons.

isolation valves

A valve designed to isolate equipment for maintenance purposes. 


A means of measuring turbidity in water by using an instrument called a nephelometer. A nephelometer passes light through a sample, and the amount of light scattered at a 90-degree angle is then measured in units of NTU.


Nephelometric Turbidity Units: a measure of clarity of water. (See Turbidity)


1 pascal = 1 Newton/m2

pathogenic organisms

Organisms, including bacteria, viruses, or cysts, capable of causing diseases (giardiasis, cryptosporidiosis, typhoid, cholera, dysentery) in a host (such as a person). There are many types of organisms that do NOT cause disease. These organisms are called non-pathogenic.

peak demand

The maximum momentary load placed on a water treatment plant, pumping station, or distribution system. This demand is usually the maximum average load in one hour or less but may be specified as the instantaneous load or the load during some other short time period.

plug flow

A type of flow that occurs in tanks, basins, or reactors when a slug of water moves through a tank without ever dispersing or mixing with the rest of the water flowing through the tank.

potable water

Water that requires no further treatment and is safe for public consumption. 


An Imperial unit of measurement used to express the volume or weight of a material dissolved in a water solution. PPM is equivalent to milligrams per litre (mg/L) which is the preferred unit for measurement. 


A force acting on a given area. The pressure is calculated by dividing the force by the area over which it is acting. The metric unit of pressure is the Pascal (kPa) and the imperial unit is pound per square inch (psi).

pressure gauge

Instrument used to measure pressure.

pressure tank

A water tank that is under pressure. Used in water systems to maintain pressure and provide storage.


Single-celled microorganisms with a more complex physiology than viruses and bacteria. Giardia and Cryptosporidium are the two main protozoa of concern. 


Pound per Square Inch: An imperial unit of pressure. 1 psi = 1 pound per square inch.


A supplier or provider of water.

raw water

Water in its natural state, prior to any treatment. Usually the water entering the first treatment process of a water treatment plan


A pond, lake, basin, or other structure (natural or human-made) that stores, regulates, or controls water.

residual chlorine

The amount of free and/or available chlorine remaining after a given contact time under specified conditions.


Risk, for the purposes of source assessments, is a factor generally defined as the probability (likelihood) that harm, injury or loss will occur to people or infrastructure, multiplied by the magnitude (consequence) of those hazards occuring.

SDS (Safety Data Sheets)

Documents that provide information about hazardous products and offer advice about safety precautions. See also: WHMIS


Dense and heavy solid materials that settle by gravity to the bottom of a basin or a tank within 4 hours. 

small water system (SWS)

Water systems serving fewer than 500 people in a 24-hour period, as defined by the Government of BC.

solenoid valve

A valve that is electrically controlled to control flow.


A liquid containing a dissolved substance. The dissolved substance is called the solute. The liquid used to dissolve the solute is called the solvent.

source assessment

Source water assessments (SWAs) provide information about sources of drinking water used by public water systems. SWAs are studies or reports developed by water suppliers with participation from technical advisors. 

source water

Source water is the raw, untreated groundwater and/or surface water that supplies your water intake or well.

surface water

All water naturally open to the atmosphere (rivers, lakes, reservoirs, streams, impoundments, seas, estuaries, ice caps, glaciers, etc.). It also refers to springs, wells, or other collectors that are directly influenced by surface water.

swab or scour

A maintenance procedure where pipes are cleaned by physically scrubbing the inner surface of the piping.

TOC (Total Organic Carbon)

TOC measures the amount of organic carbon in water.

Total Chlorine

Free chlorine and combined chlorine.


The cloudy and opaque appearance of water. It is caused by the presence of suspended and colloidal matter. In the waterworks field, a turbidity measurement is used to indicate the clarity of water. It is measured in NTU (Nephelometric Turbidity Units).

turnover rate

The time between when water enters and leaves a storage structure such as a reservoir.


A membrane filter process used for the removal of suspended and organic compounds in an aqueous (watery) solution.  Removes particles with pore sizes which can range from 0.1 um to 0.05 um.

ultraviolet (UV)

A specific wavelength (180nm - 800nm) in the invisible spectrum of light. It is produced by a device used for disinfection of water, to inactivate pathogenic microorganisms. UV may not be effective for viral control.


A device which is used to control isolate or flow in a piping system.


A very simple life form that only multiplies inside the living cells of a host; average diameter of 1/10,000 mm.

Water Licence

Authorized approval or licence provided by the province for the withdrawal of water from the environment. 


Distribution pipes that convey potable water to the consumer. 


A watershed is an area of land that catches rain and snow and drains or seeps into a marsh, stream, river, lake or groundwater. Watersheds can cross municipal, provincial and even international borders. They come in all shapes and sizes and can vary from millions of acres, like the land that drains into the Great lakes, to a few acres that drain into a pond.


A wall or a mechanical device used to control flow (from settling tanks and clarifiers) to ensure a uniform flow rate and to avoid short-circuiting.

well log

Records kept during well drilling that record the type of soil encountered, at what depths, and some characteristics of the aquifer.

WHMIS (Workplace Hazardous Materials Information System)

A global system designed to provide clear information to workers about the hazards of the materials they are using in the workplace. The three main components of WHMIS are: labelling, safety data sheets, and education for workers.